Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) AS 1100.101—1992 Australian StandardR Technical drawing Part 101: General principles This Australian Standard was prepared by Committee ME/72, Technical Drawing. It was approved on behalf of the Council of Standards Australia on 25 August 1992 and published on 16 November 1992. The following interests are represented on Committee ME/72: Association of Consulting Engineers, Australia Australian Chamber of Commerce Bureau of Steel Manufacturers of Australia Confederation of Australian Industry Department of Administrative Services Department of Defence Department of Employment and Technical and Further Education, South Australia Institute of Draftsmen, Australia Institute of Industrial Arts Institution of Engineers, Australia Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) Master Builders — Construction and Housing Association, Australia N.S.W Technical and Further Education Commission Public Works Department, N.S.W. University of New South Wales University of Queensland Additional interests participating in preparation of Standard: Australian Institute of Steel Construction University of Technology, Sydney Review of Australian Standards. To keep abreast of progress in industry, Australian Standards are subject to periodic review and are kept up to date by the issue of amendments or new editions as necessary. It is important therefore that Standards users ensure that they are in possession of the latest edition, and any amendments thereto. Full details of all Australian Standards and related publications will be found in the Standards Australia Catalogue of Publications; this information is supplemented each month by the magazine ‘The Australian Standard’, which subscribing members receive, and which gives details of new publications, new editions and amendments, and of withdrawn Standards. Suggestions for improvements to Australian Standards, addressed to the head office of Standards Australia, are welcomed. Notification of any inaccuracy or ambiguity found in an Australian Standard should be made without delay in order that the matter may be investigated and appropriate action taken. This Standard was issued in draft form for comment as DR 90110. AS 1100.101—1992 Australian StandardR Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) Technical drawing Part 101: General principles For history before 1992, see Preface. Second edition AS 1100.101—1992. Incorporating Amdt 1-1994 PUBLISHED BY STANDARDS AUSTRALIA (STANDARDS ASSOCIATION OF AUSTRALIA) 1 THE CRESCENT, HOMEBUSH, NSW 2140 ISBN 0 7262 7806 8 PREFACE This Standard was prepared by the Standards Australia Committee on Technical Drawing to supersede AS 1101.101–1984. AS 1100.101–1984 was a revision and amalgamation of AS 1100 Part 1–1977; Part 2–1975; Part 3–1971; Part 4–1972; Part 5–1973; Part 6 first published 1973 and revised in 1980; Part 7 first published 1972 and revised in 1978; and Part 8–1975. AS 1100 Parts 1 to 8 ran concurrently with AS CZ1.1 of 1976 which was withdrawn in 1982. AS CZ1.1 was a revision of AS CZ1 which was first published in 1941, with further editions published in 1944, 1946, 1951, 1966 and 1973. The 1966 edition also superseded AS Z8 of 1956 (endorsement of BS 308.2–1953 without amendment). The AS CZ1 Standards were endorsements of The Institution of Engineers, Australia publications entitled, Engineering Drawing Practice. The document from which these publications originated, was published by the Institution under the title, Recommended Engineering Drawing Practice, but this was not endorsed by this Association. This Standard is one of a series dealing with technical drawing, the other Standards in the series being as follows: Part 201: Part 301: Part 401: Part 501: Mechanical drawing Architectural drawing Engineering survey and engineering survey design drawing Structural engineering drawing In the preparation of this Standard, the committee took account of changes in Australian technical drawing practice and recommendations of the International Organization for Standardization. Also considered were the equivalent British, American, and Canadian Standards. Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) In its preparation many minor changes in the layout of the text and figures have taken place resulting in greater consistency and improved ease of use of the document. The committee considers it important that this document will be applicable to all sectors of the technical field. For instance, although many of the examples are of a mechanical nature, the principles are applicable to all fields of technical drawing. Accordingly, wherever necessary, examples have been expanded to show other applications of the principles. Clarity of expression in defining the designer’s requirements and in the interpretation of these requirements has been considered at all times. The introduction of symbols now plays an important part in drawing practice so that language barriers in reading drawings are reduced to a minimum and the valuable drafting time spent inserting notes is minimized. The section on dimensioning, which was formerly in AS 1101.201, has been rearranged to make it easier to read and updated to Australian and International practice. The use of computer–aided drafting (CAD) to produce technical drawings is acknowledged. In line with the practice of international Standards committees dealing with areas related to technical drawings, the requirements and principles of this Standard shall apply to users of CAD systems. This Standard is in agreement with the following International Standards: ISO 128 Technical drawings — General principles of presentation ISO 129 Technical drawings — Dimensioning — General principles, definitions, methods of execution and special indications ISO 406 Technical drawing — Tolerancing of linear and angular dimensions ISO 1101 Technical drawings — Geometrical tolerancing — Tolerancing of form orientation, location and run–out — Generalities, definitions, symbols, indications on drawings ISO 1660 Technical drawings — Dimensioning and tolerancing of profiles ISO 3040 Technical drawings — Dimensioning and tolerancing — Cones ISO 3098/1 Technical drawings — Lettering, Part 1: Currently used characters ISO 5455 Technical drawings — Scales ISO 5459 Technical drawings — Geometrical tolerancing — Datums and datum–systems for geometrical tolerances ISO 6410 Technical drawings — Conventional representation of threaded parts CONTENTS Page SECTION 1 1.1 1.2 1.3 1.4 1.5 SCOPE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . APPLICATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . REFERENCED DOCUMENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ABBREVIATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . SURFACE TEXTURE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . SECTION 2 2.1 2.2 2.3 2.4 2.5 Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) 4.1 4.2 4.3 SCALES 55 55 55 55 56 PROJECTIONS IDENTIFICATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . TYPES OF PROJECTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ORTHOGONAL PROJECTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . SPATIAL GEOMETRY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . AXONOMETRIC PROJECTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . OBLIQUE PROJECTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . PERSPECTIVE PROJECTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . OTHER DETAILS — PICTORIAL DRAWINGS . . . . . . . . . . . . . . . . . . . . . SECTION 7 7.1 7.2 7.3 7.4 LETTERS, NUMERALS AND SYMBOLS GENERAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . TERMINOLOGY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . INDICATION OF SCALES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . SCALE RATIOS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . LARGE SCALE DRAWINGS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . SECTION 6 6.1 6.2 6.3 6.4 6.5 6.6 6.7 6.8 32 33 34 34 34 43 43 LETTERS AND NUMERALS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45 ITEM REFERENCES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50 SYMBOLS AND TERMINATORS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50 SECTION 5 5.1 5.2 5.3 5.4 5.5 15 15 16 16 17 LINES TYPES OF LINES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . DIMENSIONS OF LINES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . LINE SPACING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . LINE DENSITY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . TYPICAL APPLICATION OF LINES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . SPECIAL APPLICATIONS OF LINES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ORDER OF PRIORITY OF COINCIDENT LINES . . . . . . . . . . . . . . . . . . . SECTION 4 5 5 5 6 6 MATERIALS, SIZES AND LAYOUT OF DRAWING SHEETS SCOPE OF SECTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . TYPES OF DRAWINGS AND RELATED TERMINOLOGY . . . . . . . . . . . MATERIALS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . SIZE OF DRAWING SHEETS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . LAYOUT OF DRAWINGS SHEETS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . SECTION 3 3.1 3.2 3.3 3.4 3.5 3.6 3.7 SCOPE AND GENERAL 57 58 58 62 65 74 77 80 SECTIONS GENERAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . CUTTING PLANES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . HATCHING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . SECTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82 82 83 87 Page SECTION 8 DIMENSIONING 8.1 8.2 8.3 8.4 SCOPE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95 GENERAL DIMENSIONING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95 GENERAL TOLERANCES AND RELATED PRINCIPLES . . . . . . . . . . . 119 DIMENSIONING AND TOLERANCING AND RELATED PRINCIPLES—GEOMETRY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 142 8.5 INTERPRETATION OF MAXIMUM MATERIAL CONDITION . . . . . . . . 155 8.6 DATUM SPECIFICATION AND INTERPRETATION . . . . . . . . . . . . . . . . 155 8.7 VIRTUAL CONDITION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 161 8.8 SCREW THREADS — ORIENTATION AND LOCATION . . . . . . . . . . . . 161 8.9 GEARS AND SPLINES — ORIENTATION AND LOCATION . . . . . . . . 165 8.10 TOLERANCES OF POSITION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 165 8.11 TOLERANCES OF FORM, PROFILE, ORIENTATION, AND RUNOUT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 190 SECTION 9 9.1 9.2 9.3 CONVENTIONAL REPRESENTATIONS SCOPE OF SECTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 206 METHOD OF PRESENTATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 206 REPRESENTATION OF FEATURES AND PARTS . . . . . . . . . . . . . . . . . 206 Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) APPENDICES A SOME COMPARISONS OF ISO STANDARDS WITH THIS STANDARD AND OTHER NATIONAL STANDARDS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B EXAMPLES OF GEOMETRY TOLERANCE DISPLAY . . . . . . . . . . . . . . . . C AXONOMETRIC PROJECTION — ADDITIONAL INFORMATION . . . . . . D OBLIQUE PROJECTION — ANGLE OF LINE OF SIGHT . . . . . . . . . . . . . . E MAXIMUM MATERIAL PRINCIPLE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . F ORIENTATION OF ACTUAL LINES AND SURFACES . . . . . . . . . . . . . . . . . G COMPARISON OF COORDINATE AND POSITION TOLERANCING . . . . H INTERPRETATION OF DATUMS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 214 217 219 223 225 228 229 232 INDEX . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 235 E Copyright — STANDARDS AUSTRALIA Users of Standards are reminded that copyright subsists in all Standards Australia publications and software. Except where the Copyright Act allows and except where provided for below no publications or software produced by Standards Australia may be reproduced, stored in a retrieval system in any form or transmitted by any means without prior permission in writing from Standards Australia. Permission may be conditional on an appropriate royalty payment. Requests for permission and information on commercial software royalties should be directed to the head office of Standards Australia. Standards Australia will permit up to 10 percent of the technical content pages of a Standard to be copied for use exclusively in–house by purchasers of the Standard without payment of a royalty or advice to Standards Australia. Standards Australia will also permit the inclusion of its copyright material in computer software programs for no royalty payment provided such programs are used exclusively in–house by the creators of the programs. Care should be taken to ensure that material used is from the current edition of the Standard and that it is updated whenever the Standard is amended or revised. The number and date of the Standard should therefore be clearly identified. The use of material in print form or in computer software programs to be used commercially, with or without payment, or in commercial contracts is subject to the payment of a royalty. This policy may be varied by Standards Australia at any time. 5 AS 1100.101—1992 STANDARDS AUSTRALIA Australian Standard Technical drawing Part 101: General principles Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) SECTION 1 SCOPE AND GENERAL 1.1 SCOPE This Standard sets out the basic principles of technical drawing practice. Section 1 sets out abbreviations. Section 2 specifies materials, sizes, and layout of drawing sheets. Section 3 specifies the types and minimum thicknesses of lines to be used and shows typical examples of their application. Section 4 sets out the requirements for distinct uniform letters, numerals, and symbols. Section 5 sets out recommended scales and their application. Section 6 sets out methods of projection and of indication of the various views of an object. Section 7 sets out methods of indicating section and provides information on conventions used in sectioning. Section 8 sets out recommendations for dimensioning including size and geometry tolerancing. Section 9 specifies conventions used for the representation of components and repetitive features of components. Appendices provide information on the various projection methods, geometry tolerancing and comparison with other Standards. NOTE: All drawings in this Standard are drawn in third angle projection unless otherwise stated. See Clause 6.3.3. 1.2 APPLICATION The basic principles given in this Standard are intended for adoption in the fields of engineering, architecture, surveying, drafting technology, and education in the preparation and interpretation of technical drawings, diagrams, charts, and tables for the purpose of conveying technical information. Technical drawings include such things as: (a) Detail drawings. (b) Assembly drawings. (c) Plans. (d) Illustrations. (e) Schematic diagrams. (f) Pictorial drawings. (g) Installation drawings. 1.3 REFERENCED DOCUMENTS The following documents are referred to in this Standard: AS 1000 The International System of Units (SI) and its application 1100 Technical drawing 1100.201 Part 201: Mechanical drawing 1100.301 Part 301: Architectural drawing 1100.401 Part 401: Engineering survey and engineering survey design drawing 1100.501 Part 501: Structural engineering drawing 1103 Diagrams, charts and tables for electrotechnology 1103.1 Part 1: Definitions and classifications 1203 Microfilming of engineering documents (35 mm) 1654 Limits and fits for engineering (Metric units) 2536 Surface texture COPYRIGHT AS 1100.101—1992 AS 3702 B129 B199 ISO 3098 3098/1 6 Item designation in electrotechnology Designs for geometric limit gauges (plain and screwed in inch units) Undercuts and runouts for screw threads Technical drawings—Lettering Part 1: Currently used characters 1.4 ABBREVIATIONS 1.4.1 General Table 1.1 gives general abbreviations for words or word combinations which are in common use on drawings for engineering, architecture, and surveying. In accordance with recommended practice, upper-case letters shall be used except where otherwise indicated in the Table. Abbreviations which are related only to a specific discipline are given in AS 1100.201 for mechanical drawing, AS 1100.301 for architectural drawing, AS 1100.401 for engineering survey and design drawing, and AS 1100.501 for structural engineering drawing. Table 1.2 gives the decoding of the abbreviations given in Table 1.1. Abbreviations should be used only where brevity and conservation of space make it necessary, and then only when their meanings are unquestionably clear to the intended reader. WHEN IN DOUBT SPELL IT OUT. Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) NOTES: 1 An abbreviation may or may not be recognized internationally. 2 The abbreviations given in Tables 1.1 and 1.2 are not exhaustive. Other abbreviations and other meanings for those given may be used, provided that — (a) their common usage in particular fields is clear; (b) the meaning is clarified on the drawing; or (c) the meaning is clarified in a reference document. 1.4.2 Use of abbreviations 1.4.2.1 Word combinations The parts of an abbreviation for a word combination shall not be isolated to derive an abbreviation for a single word or another group of words. Single abbreviations may be combined when necessary if there is no abbreviation listed for the combination. 1.4.2.2 Syntax Unless otherwise indicated herein, the same abbreviation shall be used for all tenses, the possessive case, participle endings, the singular and plural, and noun and modifying forms. 1.4.2.3 Punctuation Punctuation marks which do not appear in this Standard shall not be used with the abbreviation of a technical term. 1.4.2.4 Chemical elements Upper-case letters shall be used for the first letter of the abbreviation and lower-case for the second letter (where used). 1.5 SURFACE TEXTURE Information on surface texture related to technical drawings is given in AS 1100.201. For a more complete understanding of surface texture, reference should be made to AS 2536. COPYRIGHT 7 AS 1100.101—1992 TABLE 1.1 ABBREVIATIONS—ENCODING Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) Terms * Abbreviation abbreviation absolute acceleration access opening access panel accordance with accumulator acoustic acrylic acrylonitrile butadiene styrene active addendum adhesive aggregate agricultural agricultural pipe drain airblast circuit-breaker air condition air valve alternating current amendment American National Standards Institute anhydrous approximate aqueous arrangement asbestos assembly Association Francaise de Normalization assumed datum atmosphere audio frequency automatic auxiliary average ABBR ABS ACCEL AO AP A/W ACC ACST ACRY ABS A ADD ADH AGGR AG APD ABCB AIR COND AV AC AMDT ANSI ANHYD APPROX AQ ARRGT ASB ASSY AFNOR ASSD ATM AF AUTO AUX AVG baffle baseplate basin bath bearer bearing benchmark bitumen bitumen lined block board boiling water unit bottom boundary trap bracket brass brick brickwork Brinell hardness number British Standards Institution bronze bucket building building line bulkhead bullnose BAF BPL B BTH BRR BRG BM BIT BL BLK BD BWU BOT BT BRKT BRS BK BWK HB BSI BRZ BKT BLDG BL BHD BN cabinet cadmium plated calculated canopy cantilever capacity casing cast iron cast iron pipe CAB Cd PL CALC CAN CANT CAP CSG CI CIP Terms Abbreviation cast steel caulking cavity cement cement lined centre-line centre of gravity centre-to-centre, centres cheese head chamfer channel chrome-plated chute circle circuit circuit-breaker circular hollow section circumference clear glass clock closed-circuit television coating coefficient cold-rolled steel cold water cold-water tank column composition compression computer-aided design/drafting computer-aided engineering computer-aided manufacture concentrated concentric concrete concrete block concrete ceiling concrete floor constant construction construction joint contact adhesive contour control valve coordinating corner corrected corrosion resistant (material) corrugated corrugated galvanized steel countersink countersunk head crest critical cross recess head crown (of road) cup head current transformer cut-off valve cylinder CS CLKG CAV CEM CL CL CG CRS CH HD CHAM CHNL CP CH CIRC CCT CB CHS CIRC CG CK CCTV CTG COEF CRS CW CWT COL COMPO COMP CAD CAE CAM CONC CONC CONC CB CC CF CONST CONSTR CJ CA CTR CV COORD CNR CORR CR CORR CGS CSK CSK HD CST CRIT C REC HD CRN CUP HD CT COV CYL damp-proof course dead load detail diagonal diagram diameter inside nominal outside DPC DL DET DIAG DIAG DIA* ID DN OD When used in association with a numerical value, the preferred method of expressing this abbreviation is by a symbol. (continued) COPYRIGHT AS 1100.101—1992 8 TABLE 1.1 (continued) Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) Terms Abbreviation diamond pyramid hardness number (Vickers) dilute dimension Deutsches Institut fur Normung direct current disconnector trap distance distribution switchboard drain drawing dwelling HV DIL DIM DIN DC DT DIST DSB DR DRG DWG each earth (electrical wiring) earthenware earthenware pipe easement educt vent effective efficiency effluent electric, electrical electromotive force elevation engine, engineering equivalent estimate existing expansion expansion joint external extra-high voltage extra-low voltage extrude EA E EW EWP EMT EV EFF EFF EFF ELEC EMF ELEV ENG EQUIV EST EXST EXP EJ EXT EHV ELV EXTD fibre-reinforced plastic figure fillister head finished floor height finished ground height fire alarm fire detector fire extinguisher fire hose rack/reel fire hydrant fire indicator panel fire plug fire resistant fire service pipe fire water service flange flat floor floor height floor sump flush fitting forward framework frequency audio high intermediate low medium ultra-high very-high frequency modulated FRP FIG FILL HD FFHT FGHT FA FD FE FHR FH FIP FP FR FSP FWS FLG FL FLR FHT FS FF FWD FWK FREQ AF HF IF LF MF UHF VHF FM galvanize galvanized iron galvanized iron pipe GALV GI GIP Terms Abbreviation garage gas cock gas main gas meter gas turret gate valve general arrangement general purpose outlet geometric reference frame grade grease trap grid ground ground height group gully disconnector trap gully pit gully trap GAR GC GM GM GT GV GA GPO GRF GR GT GD GND GHT GP GDT GP GT hand hard hardboard hardcore hardwood head cheese cross recess countersunk cup fillister hexagon hexagon socket mushroom raised countersunk round square heater heavy duty height hexagon high frequency high pressure high strength high-tensile steel high voltage hollow section circular rectangular square horizontal hose cock hot-rolled steel hot water hot water unit hydrant hydrant point hydraulic hydrogen ion exponent HD HD HBD HC HWD HD CH HD C REC HD CSK HD CUP HD FILL HD HEX HD HEX SOC HD MUSH HD RSD CSK HD RD HD SQ HD HTR HD HT HEX HF HP HS HTS HV include incorporate indicator induct vent inspection chamber inspection opening inspection pit insoluble insulated or insulation integrated circuit interceptor trap intermediate frequency internal International Electrotechnical Commission International Organization for Standardization INCL INC IND IV IC IO IP INSOL INSUL IC IT IF INT IEC ISO CHS RHS SHS HORIZ HC HRS HW HWU H HP HYD pH (continued) COPYRIGHT 9 AS 1100.101—1992 TABLE 1.1 (continued) Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) Terms * Abbreviation International System of Units (Systeme International d’Unites) intersection point invert invert level (height) isolator SI IP INV IH ISOL Japanese Industrial Standards Committee joint junction JISC JT JUNC landing latent heat least material condition left hand length level lining liquefied natural gas liquefied petroleum gas liquid live load longitudinal louvre low frequency low pressure low voltage lubricate LDG LAT HT LMC LH LG LEV LNG LNG LPG LIQ LL LONG LVR LF LP LV LUB machine main switchboard malleable iron manhole mark masonry material maximum maximum material condition mechanical medium pressure melting point meter (instrument) minimum miscellaneous mixing value modification modulus of elasticity modulus, section moment of inertia mounting M/C MSB MI MH MK MSRY MATL MAX MMC MECH MP MP M MIN MISC MV MOD E Z I MTG negative neutral (electrical) nickel plated nominal nominal diameter nominal size North not to scale number NEG N NP NOM DN NS N NTS * NO octagon oil circuit-breaker oil interceptor trap opposite oven overall overhead OCT OCB OIT OPP O OA OH parallel parallel flange channel part partition passivate pattern PAR * PFC PT PTN PASS PATT Terms Abbreviation pedestal per annum phase pipe pipeline phosphor bronze plasterboard plate glass plywood pneumatic polytetrafluoroethylene polyvinyl acetate polyvinyl chloride portion position positive potential difference precast precipitate (noun) prefabricated preliminary pressure pressure-relief pipe printed circuit board printed wiring board push-button PED PA PH P PL PH BRZ PBD PG PLY PNEU PTFE PVA PVC PORT POSN * POS PD PC PPT PREFAB PRELIM PRESS PRP PCB PWB PB quantity QTY radius recovery peg rectangular rectangular hollow section reference reference line reference mark reflux valve reinforced concrete reinforced-concrete pipe reinforcement relative humidity relief valve required right hand right of way road Rockwell hardness A B C rolled-steel angle rolled-steel channel rolled-steel joist round runnel RAD * RP RECT RHS REF RL RM RV RC RCP REINF RH RV REQD RH ROW RD safety valve satin chrome plated schedule screw section septic tank sewer sewer drain sewer vent sewer vent pipe sheet sketch soakage pit socket solution specification spherical spigot SV SCP SCHED SCR SECT ST SEW SD SV SVP SH SK SKP SOC SOLN SPEC SPHER * SPT HRA HRB HRC RSA RSC RSJ RD R When used in association with a numerical value, the preferred method of expressing this abbreviation is by a symbol. COPYRIGHT (continued) AS 1100.101—1992 10 TABLE 1.1 (continued) Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) Terms * Abbreviation Terms Abbreviation spring steel sprinkler square square head square hollow section standard standard temperature and pressure station steam trap steel sterilizer stopcock stop tap stop valve stormwater drain stormwater pit straight street structural floor level surface level switch switchboard symmetry SPR STL SPR SQ SQ HD SHS STD STP STA ST STL STER SC ST SV SWD SWP STR ST SFL SL SW SWBD SYM ultra-high frequency undercut underground underside universal beam universal bearing pile universal column utility UHF UCUT U/G U/S UB UBP UC UTIL vacuum vapour barrier vapour density vapour pressure vent pipe ventilator verandah vertical very-high frequency Vickers hardness vinyl tiles vitrified clay vitrified clay pipe volume VAC VB VD VP VP VENT VER VERT VHF HV VT VC VCP VOL tangent point tank water level telephone television temperature tensile strength thermoplastic insulated thread time switch tolerance tough plastics sheathed tough rubber sheathed transformer transmitter transverse true position true profile typical TP TWL TEL TV TEMP TS TPI THD TS TOL TPS TRS XFMR TX TRANSV TP* TP* TYP wallboard wash trough washing machine waste pipe water gauge water level, waterline water main water meter waterproof membrane with (combination form) without wood wrought iron WBD WT WM WP WG WL WM WMR WPM W/........ W/O WD WI yield point YP zinc plated Zn PLT ultimate ULT When used in association with a numerical value, the preferred method of expressing this abbreviation is by a symbol. COPYRIGHT 11 AS 1100.101—1992 TABLE 1.2 ABBREVIATIONS—DECODING Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) Abbreviation Terms Abbreviation A ABBR ABCB ABS ABS AC ACC ACCEL ACRY ACST ADD ADH AF AFNOR AG AGGR AIR COND AMDT ANHYD ANSI AO AP APD APPROX AQ ARRGT ASB ASSD ASSY ATM AUTO AUX AVG AV A/W active abbreviation airblast circuit-breaker absolute acrylonitrile butadiene styrene alternating current accumulator acceleration acrylic acoustic addendum adhesive audio frequency Association Francaise de Normalization agricultural aggregate air condition amendment anhydrous American National Standards Institute access opening access panel agricultural pipe drain approximate aqueous arrangement asbestos assumed datum assembly atmosphere automatic auxiliary average air valve accordance with B BAF BD BHD BIT BK BKT BL BL BLDG BLK BM BN BOT BPL BRG BRKT BRR BRS BRZ BSI BT BTH BWK BWU basin baffle board bulkhead bitumen brick bucket bitumen lined building line building block benchmark bullnose bottom baseplate bearing bracket bearer brass bronze British Standards Institution boundary trap bath brickwork boiling water unit CA CAB CAD CAE CALC CAM CAN CANT CAP contact adhesive cabinet computer-aided design/drafting computer-aided engineering calculated computer-aided manufacture canopy cantilever capacity Terms CAV CB CB CC CCT CCTV Cd PL CEM CF CG CG CGS CH CHAM CH HD CHNL CHS CI CIP CIRC CIRC CJ CK CL CL CLKG CNR COEF COL COMP COMPO CONC CONC CONC CONST CONSTR COORD CORR CORR COV CP C REC HD CR CRIT CRN CRS CRS CS CSG CSK CSK HD CST CT CTG CTR CUP HD CV CW CWT CYL cavity circuit-breaker concrete block concrete ceiling circuit closed-circuit television cadmium plated cement concrete floor centre of gravity clear glass corrugated galvanized steel chute chamfer cheese head channel circular hollow section cast iron cast iron pipe circle circumference construction joint clock cement lined centre-line caulking corner coefficient column compression composition concentrated concentric concrete constant construction coordinating corrected corrugated cut-off valve chrome-plated cross recess head corrosion resistant (material) critical crown (of road) centre-to-centre, centres cold-rolled steel cast steel casing countersunk countersunk head crest current transformer coating contour cup head control valve cold water cold-water tank cylinder DC DET DIA DIAG DIAG DIL DIM DIN DIST DL DN DPC direct current detail diameter diagonal diagram dilute dimension Deutsches Institut fur Normung distance dead load nominal diameter damp-proof course (continued) COPYRIGHT AS 1100.101—1992 12 TABLE 1.2 (continued) Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) Abbreviation Terms DR DRG DSB DT DWG drain drawing distribution switchboard disconnector trap dwelling E E EA EFF EFF EFF EHV EJ ELEC ELEV ELV EMF EMT ENG EQUIV EST EV EW EWP EXP EXST EXT EXTD earth (electrical wiring) modulus of elasticity each effective efficiency effluent extra-high voltage expansion joint electric, electrical elevation extra-low voltage electromotive force easement engine, engineering equivalent estimate educt vent earthenware earthenware pipe expansion existing external extrude FA FD FE FF FFHT FGHT FH FHR FIP FIG FILL HD FL FHT FLG FLR FM FP FR FREQ FRP FS FSP FWD FWK FWS fire alarm fire detector fire extinguisher flush fitting finished floor height finished ground height fire hydrant fire hose rack/reel fire indicator panel figure fillister head flat floor height flange floor frequency modulated fire plug fire resistant frequency fibre-reinforced plastic floor sump fire service pipe forward framework fire water service GA GALV GAR GC GD GDT GHT GI GIP GM GM GND GP GP GPO GR GRF GT general arrangement galvanize garage gas cock grid gully disconnector trap ground height galvanized iron galvanized iron pipe gas main gas meter ground group gully pit general purpose outlet grade geometric reference frame gas turret Abbreviation Terms GT GT GV grease trap gully trap gate valve H HB HBD HC HC HD HD HD HD HEX HEX HD HEX SOC HD HF HORIZ HP HP HRA, HRB, HRC HRS HS HT HTR HTS HV HV HW HWU HWD HYD hydrant Brinell hardness number hardboard hardcore hose cock hand hard head heavy duty hexagon hexagon head hexagon socket head high frequency horizontal hydrant point high pressure Rockwell hardness (A, B, C) hot-rolled steel high strength height heater high-tensile steel diamond pyramid hardness number (Vickers) high voltage hot water hot water unit hardwood hydraulic I IC IC ID IEC IF IH INC INCL IND INSOL INSUL INT INV IO IP IP ISO ISOL IT IV moment of inertia inspection chamber integrated circuit inside diameter International Electrotechnical Commission intermediate frequency invert level (height) incorporate include indicator insoluble insulated or insulation internal invert inspection opening inspection pit intersection point International Organization for Standardization isolator interceptor trap induct vent JISC JT JUNC Japanese industrial Standards Committee joint junction LAT HT LDG LEV LF LG LH LIQ LL LMC LNG LNG LONG LP LPG LUB latent heat landing level low frequency length left hand liquid live load least material condition lining liquefied naturel gas longitudinal low pressure liquefied petroleum gas lubricate (continued) COPYRIGHT 13 AS 1100.101—1992 TABLE 1.2 (continued) Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) Abbreviation Terms LV LVR low voltage louvre M MATL MAX M/C MECH MF MH MI MIN MISC MK MMC MOD MP MP MSB MSRY MTG MUSH HD MV meter (instrument) material maximum machine mechanical medium frequency manhole malleable iron minimum miscellaneous mark maximum material condition modification medium pressure melting point main switchboard masonry mounting mushroom head mixing valve N N NEG NO NOM NP NS NTS North neutral (electrical) negative number nominal nickel plated nominal size not to scale O OA OCB OCT OD OH OIT OPP oven overall oil circuit-breaker octagon outside diameter overhead oil interceptor trap opposite P PA PAR PASS PATT PB PBD PC PCB pipe per annum parallel passivate pattern push-button plasterboard precast printed circuit board PD PED PFC PG PH pH PH BRZ PL PLY PNEU PORT POS POSN PPT PREFAB PRELIM PRESS PRP PT PTFE PTN potential difference pedestal parallel flange channel plate glass phase hydrogen ion exponent phosphor bronze pipeline plywood pneumatic portion positive position precipitate (noun) prefabricated preliminary pressure pressure-relief pipe part polytetrafluoroethylene partition Abbreviation Terms PVA PVC PWB polyvinyl acetate polyvinyl chloride printed wiring board QTY quantity R RAD RC RCP RD RD RD HD RECT REF REINF REQD RH RH RHS RL RM ROW RP RSA RSC RSD RSD CSK HD RSJ RV RV runnel radius reinforced concrete reinforced-concrete pipe road round round head rectangular reference reinforcement required relative humidity right hand rectangular hollow section reference line reference mark right of way recovery peg rolled-steel angle rolled-steel channel raised raised countersunk head rolled-steel joist reflux valve relief valve SC SCHED SCP SCR SD SECT SEW SFL SH SHS SI stopcock schedule satin chrome plated screw sewer drain section sewer structural floor level sheet square hollow section International System of Units (Systeme International d’Unites) sketch soakage pit surface level socket solution specification spherical sprinkler spring steel spigot square square head septic tank steam trap street stop tap station standard sterilizer steel standard temperature and pressure straight safety valve sewer vent stop valve sewer vent pipe switch switchboard stormwater drain stormwater pit symmetry SK SKP SL SOC SOLN SPEC SPHER SPR SPR STL SPT SQ SQ HD ST ST ST ST STA STD STER STL STP STR SV SV SV SVP SW SWBD SWD SWP SYM (continued) COPYRIGHT AS 1100.101—1992 14 TABLE 1.2 (continued) Abbreviation Terms telephone temperature thread tolerance tangent point true position true profile thermoplastic insulated tough plastics sheathed transverse tough rubber sheathed tensile strength time switch television tank water level transmitter typical UB UBP UC UCUT U/G UHF ULT U/S UTIL universal beam universal bearing pile universal column undercut underground ultra-high frequency ultimate underside utility VAC VB VC vacuum vapour barrier vitrified clay Terms VCP VD VENT VER VERT VHF VOL VP VP VT vitrified clay pipe vapour density ventilator verandah vertical very-high frequency volume vapour pressure vent pipe vinyl tiles W/........ WBD WD WG WI WL WM WM WMR W/O WP WPM WT with (combination form) wallboard wood water gauge wrought iron water level, waterline washing machine water main water meter without waste pipe waterproof membrane wash trough XFMR transformer YP yield point Z Zn PLT modulus, section modulus zinc plated Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) TEL TEMP THD TOL TP TP TP TPI TPS TRANSV TRS TS TS TV TWL TX TYP Abbreviation COPYRIGHT 15 SECTION 2 AS 1100.101—1992 MATERIALS, SIZES AND LAYOUT OF DRAWING SHEETS 2.1 SCOPE OF SECTION This Section specifies requirements for standard drawing sheets and covers materials, designation, sizes, tolerances, and layout details. Certain information is also given for roll drawings. 2.2 TYPES OF DRAWINGS AND RELATED TERMINOLOGY 2.2.1 Drawing—a document consisting of one or more drawing sheets presenting information pictorially or by textual matter (or both). NOTE: A drawing is normally identified by a drawing number and title. 2.2.2 Arrangement drawing—a drawing depicting in any form of projection the relationships of major units or systems of the item depicted. Arrangement drawings may be with or without controlling dimensions. 2.2.3 Assembly drawing—a drawing depicting an assembly or subassembly. NOTE: An assembly drawing is sometimes referred to as a general assembly. 2.2.4 Control drawing—a drawing that establishes parameters for the development, procurement or construction of an item, or for the co-functioning of items in an installation or layout. Parameters include configurations and configuration limitations, performanceand test requirements, access clearances, and mass and space limitations. NOTE: Control drawings may be further classified as envelope, specification control, source control, interface control, and installation control types. 2.2.5 Detail assembly drawing—a drawing depicting an assembly on which one or more parts are detailed in the assembly view or on separate detail views. 2.2.6 Detail drawing—a drawing depicting end product requirements for the parts delineated on the drawing. Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) NOTE: Not to be confused with a ‘Detail’ (see Clause 6.3.8). 2.2.7 Diagrammatic drawing (or diagram)—a drawing delineating, by means of symbols and lines, the characteristics and relationships of items forming an assembly or system. 2.2.8 General arrangement drawing—an arrangement drawing where the item depicted is the end product. 2.2.9 Installation drawing—a drawing specifying complete information necessary to install an item or items relative to the supporting structure or to associated items. 2.2.10 Monodetail drawing—a detail drawing delineating a single part. 2.2.11 Multidetail drawing—a detail drawing delineating two or more uniquely identified parts on the same drawing sheet. 2.2.12 Tabulated drawing—a drawing showing similar configurations, parts, items or assemblies with the variations in characteristics given in tabular form. 2.2.13 Electrotechnology drawings For electrotechnology drawings, see AS 1103.1. 2.2.14 Works as executed drawing—a record of work actually completed. 2.2.15 Assembly (subassembly)—a set of two or more items fitted together to perform a specific function. NOTE: A subassembly is a portion of an assembly. 2.2.16 End product—an item, either an individual part, assembly, structure, or project, in its final or complete state. 2.2.17 Flow chart—a diagram in which objects are shown in a simplified way by means of graphical symbols (and letter symbols) in order to make the functional relationships or the assembly of an object clear. 2.2.18 Installation—a number of parts or subassemblies or any combination thereof fitted together to perform a specific function, in association with an appropriate structure or enclosure. 2.2.19 Part—one piece (member) or two or more pieces (members) joined together which cannot normally be separated without destruction or impairment of designed use. NOTE: A part is sometimes described as a component. 2.2.20 Part number—a number assigned to identify uniquely a specific part. See also Note to Clause 4.2.2.2. COPYRIGHT AS 1100.101—1992 16 2.2.21 System—a combination of parts and assemblies fitted together to perform a specific operational function or functions. 2.3 MATERIALS Blanks or preprinted sheets for drawings and documents may be transparent, translucent or opaque, but should be matt on the drafting surface. Their quality shall be chosen to obtain the best contrast between background and lines. See also Clause 3.4. NOTES: 1 If adhesive overlays are to be used, consideration must be given to the effects of dust, heat and ageing as these may result in defects in the reprographic process. 2 Edge binding is not recommended unless the binding and the drafting materials are compatible for shrinkage. 2.4 SIZE OF DRAWING SHEETS 2.4.1 Preferred sizes The preferred size of drawing sheets shall be the ISO-A series for which the designation and dimensions are as given in Table 2.1. Preferred size drawing sheets, with slightly wider borders to take account of preprinting considerations, shall have dimensions as given in Table 2.2. Such sheets shall be additionally designated by the prefix R, i.e. RA0, RA1, RA2, RA3, and RA4. Where drawing sheets of a greater length are required, they should be selected from and have dimensions in accordance with one of the series given in Table 2.3. Such sheets shall be designated A3 × 3, A3 × 4, A4 × 3, A4 × 4, and A4 × 5. Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) 2.4.2 Non-preferred sizes The non-preferred size of drawing sheets shall be the ISO-B series for which the designations and dimensions are as given in Table 2.4. Non-preferred size drawing sheets, with slightly wider borders to take account of preprinting considerations, shall have dimensions as given in Table 2.5. Such sheets shall be additionally designated by the prefix R, i.e. RB1, RB2, RB3, and RB4. 2.4.3 Roll drawings Standard widths of roll drawings shall be 860 mm and 610 mm. Lengths of the roll drawing sheets shall be determined to suit the requirements of the individual drawings. NOTE: Care should be taken to ensure that the chosen length of a roll drawing is suitable for microfilming (see AS 1203), and for folding purposes. 2.4.4 Tolerances The cut sizes in Tables 2.1 to 2.5 shall be subject to the following tolerances: For dimensions ≤600 mm—±2 mm. For dimensions >600 mm—±3 mm. Neither diagonal of any cut sheet shall exceed the diagonal of the appropriate maximum length and width, nor shall it be less than the diagonal of the appropriate minimum length and width. For the purpose of checking the sheet sizes, the material shall be conditioned at 20 ±2°C at a relative humidity of 65 ±2 percent and measured under these conditions. TABLE 2.1 DIMENSIONS OF PREFERRED SHEETS Standard designation Cut sheet dimensions mm A0 A1 A2 A3 A4 841 × 1189 594 × 841 420 × 594 297 × 420 210 × 297 TABLE 2.2 DIMENSIONS OF PREFERRED SHEETS WITH WIDER BORDERS Designation Ordering purposes only Standard Cut sheet dimensions mm RA0 RA1 RA2 RA3 RA4 A0 A1 A2 A3 A4 860 × 1220 610 × 860 430 × 610 305 × 430 215 × 305 COPYRIGHT 17 AS 1100.101—1992 TABLE 2.3 DIMENSIONS OF ELONGATED PREFERRED SHEETS Cut sheet dimensions mm Designation A3 A3 A4 A4 A4 ×3 ×4 ×3 ×4 ×5 420 × 891 420 × 1189 297 × 630 297 × 841 297 × 1051 TABLE 2.4 DIMENSIONS OF NON-PREFERRED SHEETS Designation Cut sheet dimensions mm B1 B2 B3 B4 707 × 1000 500 × 707 353 × 500 250 × 353 TABLE 2.5 DIMENSIONS OF NON-PREFERRED SHEETS WITH WIDER BORDERS Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) Designation Ordering purposes only Standard Cut sheet dimensions mm RB1 RB2 RB3 RB4 B1 B2 B3 B4 733 × 1019 510 × 723 361 × 510 255 × 361 2.5 LAYOUT OF DRAWINGS SHEETS 2.5.1 Size of borders 2.5.1.1 Sheets without filing margin Where no filing margin is required, the drawing frame and its location in relation to the edges of the sheet should be as shown in Figure 2.1. NOTE: The borders shown in Figure 2.1 are of minimum size. 2.5.1.2 Sheets with filing margin Where provision for a filing margin is required, the drawing frame and its location in relation to the edges of the sheets should be as shown in Figure 2.2. NOTE: The borders and the filing margin shown in Figure 2.2 are of minimum size. 2.5.1.3 Roll drawings Where borders are required for roll drawings, the borders of sheets should conform to the dimensions shown in Figure 2.3. 2.5.2 Print trimming line Where drawing sheets complying with Table 2.2 or Table 2.5 are used, a method of indicating the print trimming line shall be marked on the sheets. This may be by means of broken lines forming a frame as in Figure 2.4 dimensioned to the cut-sheet dimensions of preferred or non-preferred series sheets specified in Table 2.1 or Table 2.4, or by other suitable methods of indication. 2.5.3 Camera alignment marks Camera alignment marks shall be provided at the centre of each of the four sides of the drawing sheet. Marks shall be in the form of an outline arrowhead pointing outwards and should be placed outside the drawing frame. A typical example showing the allowable 6 mm wide tolerance zone for microfilm centring is given in Figure 2.5. The camera alignment marks on roll drawings shall be placed so that they comply with the requirements of AS 1203. The drawing information in the overlap regions of the microfilm frames shall be minimal. 2.5.4 Grid referencing The provision of a grid reference system is recommended for all sizes, in order to permit easy location on the drawing of details, additions, and modifications. The number of divisions should be divisible by two and be chosen in relation to the complexity of the drawing. It is recommended that the length of any side of the rectangles comprising the grid be not less than 25 mm and not more than 75 mm. The rectangles of the grid should be referenced by means of capital letters along one edge and numerals along the other edge. The numbering direction may start at the sheet corner opposite to the title block and be repeated on the opposite sides. The letters and numerals shall be placed in the borders, close to the frame at a minimum distance of 5 mm from the edges of the trimmed sheet, and shall be written in upright characters according to Section 4 (see Figure 2.5). If the number of the lettered divisions exceeds that of the alphabet, the reference letters with the extra divisions should be doubled (AA, BB, CC, etc). COPYRIGHT Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) AS 1100.101—1992 18 FIGURE 2.1 SIZE AND LOCATION OF DRAWING FRAME ON DRAWING SHEETS WITHOUT FILING MARGIN COPYRIGHT Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) 19 AS 1100.101—1992 FIGURE 2.2 SIZE AND LOCATION OF DRAWING FRAME ON DRAWING SHEETS WITH FILING MARGIN COPYRIGHT AS 1100.101—1992 20 millimetres Nominal width of borders Standard width of roll* Top and bottom On both sides a b 860 29.5 20 min. 801 610 28 20 min. 554 W Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) Width of rectangular drawing frame A * See Clause 2.4.3. FIGURE 2.3 DIMENSIONS OF DRAWING FRAME—ROLL DRAWINGS FIGURE 2.4 OVERSIZE DRAWING SHEET WITH PRINT TRIMMING LINE INDICATION 2.5.5 Sheet designation The sheet size designation number shall be indicated on the drawing, preferably in the right-hand bottom corner of the drawing frame (see Figure 2.6). Drawings prepared for microfilming shall contain means of determining the original size. This should be achieved preferably by indicating the drawing frame dimensions. These may be shown outside the drawing frame near a corner (see Figure 2.6). Alternatively a graduated line at least 150 mm long should be shown in a suitable location (see Figure 2.8). COPYRIGHT 21 AS 1100.101—1992 2.5.6 Other information The following information should be displayed on each drawing sheet in a prominent position as illustrated in Figures 2.6, 2.7, 2.8, and 2.9: (a) Indication of system of projection. (i) For third angle projection, which is the preferred system, either — (A) or (B) 3RD ANGLE PROJECTION (ii) For first angle projection, either — (A) or (B) 1ST ANGLE PROJECTION (b) Prohibition of scaling — (c) Dimensional units — DO NOT SCALE DIMENSIONS IN MILLIMETRES or other units as appropriate. (d) The Standard to which the drawing is prepared. Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) 2.5.7 Fold lines Where required, fold lines should be indicated on drawing sheets according to the method of folding used. 2.5.8 Layout 2.5.8.1 General Examples of layouts of drawing sheets are given in Figures 2.6, 2.7, 2.8, and 2.9. It is recognized that considerable latitude is necessary in the arrangement and position of title blocks, material and parts lists, and other text, and consequently the layouts illustrated should be regarded only as typical of practice. They may be modified in detail to suit the needs of any particular organization. 2.5.8.2 Detail drawings Figure 2.8 shows a sheet suitable for detail drawings. Normally, for production in quantity, only one part is shown on such a sheet, the size of which will vary to suit the actual part. The drawing and the contents of the title block should provide all the information needed for the manufacture of the part and indexing of drawing. 2.5.8.3 Assembly and multidetail drawings Figures 2.7 and 2.8 are examples of sheets suitable for assembly drawings or for drawings which show a number of parts on the same sheet. In either case, only general information is given in the title block, and particular information for the individual parts is tabulated in a material or parts list. 2.5.9 Title block Spaces shall be provided in the title block for the following information (see Figure 2.9): (a) Name of firm, organization, department. (b) Title or name of drawing. (c) Drawing number. (d) Signatures or initials and dates. In addition, the scale, method of projection, and other information considered relevant may be shown. The title block should be located in the bottom right-hand corner of the drawing sheets. For convenience of drawing layout however, the top right-hand corner may be used (see Figure 2.8). The space for the drawing number shall be located in the title block near to the corner of the sheet. In addition, other spaces for the drawing number may be located in other corners of the sheet or along the sides of the sheet to ensure that it is visible when the drawing is filed or when a print is folded (see Figure 2.8). 2.5.10 Supplementary information It is recommended that spaces also be provided to the left of the title block as may be required to provide for the inclusion of standard information relating to units of measurement, tolerances, key to machining and other symbols, treatment, finish, tool and gauge references, issue number or letter, revision information, material specification, reference drawing numbers, and other details. COPYRIGHT AS 1100.101—1992 22 2.5.11 Material or parts list Where several parts are detailed on the one sheet or an assembly of parts is shown, a tabulated material or parts list should be provided adjacent to the title block. Where the list is extensive or when more convenient, a separate sheet distinct from detail or assembly drawings may be used. Such lists should be prepared on standard size drawing sheets, with the same essential spaces as specified for the title blocks of drawings (see Figures 2.7, 2.8, 2.10, 2.11, 2.12, and 2.13). The list should also include the following information: (a) Items or part numbers. (b) Description or name of part. (c) Quantity required. (d) Material, material specification. (e) Drawing number of detail drawing. (f) Stores reference number, if applicable. The quantity column may be extended, as shown in Figure 2.10, where the same parts may be used in different assemblies or groups, e.g. in different machines or different models. 2.5.12 Thickness of format lines The format lines specified in this Standard shall conform to the thickness given in Table 2.6. NOTE: Lines used in drawing practice are specified in Section 3. TABLE 2.6 THICKNESS OF FORMAT LINES Thickness of lines mm Features Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) Sheet size A0 A1 A2, A3, A4 B1 B2 B3, B4 1.4 1.0 0.7 1.0 0.7 0.5 Grid lines (see Clause 2.5.4) 0.7 0.5 0.35 Camera alignment marks (see Clause 2.5.3) 0.5 0.35 0.25 Fold lines (see Clause 2.5.7) 0.25 0.25 0.25 Other format lines 0.35 0.25 0.18 Border lines (see Clause 2.5.1) Projection symbol (see Clause 2.5.6) Principal lines in title block (see Clause 2.5.9) 2.5.13 Lettering in drawing layouts Lettering should comply with the requirements specified in Section 4. 2.5.14 Orientation of drawings The orientation of all tables, parts and lists, and drawings (including dimensions) shall be placed so as to read either from the bottom or right-hand side of the drawing sheet (see Figures 2.10 and 2.11). COPYRIGHT Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) 23 FIGURE 2.5 TYPICAL CAMERA ALIGNMENT MARKS, REFERENCE SYSTEM, AND FOLD LINES FOR PREFERRED AND NON-PREFERRED SERIES DRAWING SHEETS COPYRIGHT AS 1100.101—1992 Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) AS 1100.101—1992 24 FIGURE 2.6 TYPICAL LAYOUT OF A DRAWING SHEET WITHOUT PARTS LIST COPYRIGHT Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) 25 Figure 2.7 TYPICAL LAYOUT OF A DRAWING SHEET WITH PARTS LIST COPYRIGHT AS 1100.101—1992 Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) AS 1100.101—1992 26 FIGURE 2.8 TYPICAL LAYOUT OF A DRAWING SHEET WITH ALTERNATIVE LOCATION OF TITLE BLOCK AND PARTS LIST COPYRIGHT Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) 27 FIGURE 2.9 TYPICAL TITLE BLOCKS COPYRIGHT AS 1100.101—1992 Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) AS 1100.101—1992 28 FIGURE 2.10 TYPICAL LAYOUT OF A PARTS LIST COPYRIGHT Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) 29 FIGURE 2.11 TECHNICAL DATA SHEET FOR COMPONENTS—ELECTROTECHNOLOGY COPYRIGHT AS 1100.101—1992 Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) AS 1100.101—1992 30 FIGURE 2.12 TECHNICAL DATA SHEET FOR RELAYS—ELECTROTECHNOLOGY COPYRIGHT Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) 31 COPYRIGHT AS 1100.101—1992 FIGURE 2.13 TECHNICAL DATA CORRELATION SHEET — ELECTROTECHNOLOGY AS 1100.101—1992 32 SECTION 3 LINES Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) 3.1 TYPES OF LINES Lines on drawings shall be selected according to their application. Preferred types are shown in Table 3.1 and shall be selected from one of the line groups given in Figure 3.1. Each type is designated by a letter. Preferred types of the lines are shown in Table 3.1 and Figure 3.1 and typical applications in Figures 3.2 to 3.18. TABLE 3.1 LINES AND APPLICATIONS NOTES: 1 It is desirable to restrict line thickness to two on any one drawing. A medium thickness line may be used by some drafting disciplines such as structural and electrical for additional clarity. Refer to drafting standards for particular disciplines for examples. 2 It is recommended that only one thickness of dashed line be used. 3 Proportions of spaces are as specified for Type G. COPYRIGHT 33 AS 1100.101—1992 Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) 3.2 DIMENSIONS OF LINES 3.2.1 Thickness The thickness of lines shall be selected from one of the line groups given in Figure 3.1, and shall be such that the thickness of any line after reproduction shall be not less than 0.18 mm. 3.2.2 Dashes The length and spacing of dashes shall be consistent, but they may vary in length depending on the complete length of the line and size of the drawing. Recommended dimensions are shown in Table 3.1. FIGURE 3.1 LINE GROUPS COPYRIGHT AS 1100.101—1992 34 3.3 LINE SPACING Parallel lines shall be drawn with a clear space between them of not less than twice the thickness of the thickest line, with a minimum space of 1 mm. Where a group of parallel lines intersect another group of parallel lines, the space between lines in each group should be not less than 2 mm. 3.4 LINE DENSITY To facilitate good quality reproduction of drawings using dyeline or microfilming processes, all lines on original drawings shall be matt, of constant density and have a high contrast with respect to the material background. Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) (I ) NOTE: Contrast is the difference between the optical density of a line and that of the sheet. The optical density of a medium is log10 0, (I1) where I0) is the amount of light falling on the surface of the medium and I 1 is the amount of light passing through the medium. A suggested minimum value for optical density is 0.7. 3.5 TYPICAL APPLICATION OF LINES 3.5.1 Type A Type A lines shall be used for the following purposes: (a) Visible outlines of features of an object (see Figure 3.3). (b) General details of structures (see Figure 3.4). (c) Landscaping and existing buildings in survey drawing (see Figure 3.2). (d) Busbars and transmission paths in electrotechnology (see Figure 3.5). 3.5.2 Type B Type B lines shall be used for the following purposes: (a) Fictitious outlines, such as minor diameters of external threads and major diameters of internal threads (see Figure 3.3). (b) Dimension lines and projection lines (see Figure 3.3). (c) Hatching (see Figures 3.3 and 3.4). (d) Leaders (see Figures 3.3 and 3.4). (e) Outlines of revolved sections (see Figure 3.3). (f) Imaginary intersection of surfaces (see Figure 3.6). Such lines should not meet the outlines. (g) Fold or tangent bend lines (see Figure 3.7). (h) Short centre-lines if Type G lines are not appropriate (see Clause 3.5.6). (i) General purpose electrical conductors and symbols (see Figure 3.5). (j) Line of intersection of principal planes (see Figure 6.18). See also Clause 3.6. 3.5.3 Types C and D Lines of Types C and D shall be used to terminate part views (see Figures 3.3 and 3.4) and part sections (see Figure 3.8). Type C is recommended for short break lines and for the S-break in cylindrical members in exterior views. Type D is recommended for long break lines, and shall extend beyond the outlines which they terminate. Both types may be used in the one view (see Figure 3.3). 3.5.4 Type E Type E lines shall be used to indicate hidden outlines and hidden edges. 3.5.5 Type F Type F lines shall be used to indicate hidden outlines of internal features of an object that are not otherwise shown, or where their use would assist or is necessary in the interpretation of the drawing (see Figure 3.9). Features located behind transparent materials shall be treated as hidden parts. It is important to guard against excessive use of hidden outlines. They should be confined to the view or views in which they are needed. The following further requirements in the use of Type F lines are illustrated in Figure 3.9: (a) Hidden outlines should always begin and end with a dash in contact with the visible or hidden outline at which they start and end, except where such a dash would form a continuation of a visible outline. (b) Dashes should join at corners, and arcs should start with dashes at the tangent points. (c) Dashes of parallel hidden outlines, when close together, should preferably be staggered. COPYRIGHT Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) 35 FIGURE 3.2 TYPICAL APPLICATION OF TYPES OF LINES — SURVEY COPYRIGHT AS 1100.101—1992 Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) AS 1100.101—1992 36 FIGURE 3.3 TYPICAL APPLICATION OF TYPES OF LINES—MECHANICAL COPYRIGHT Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) 37 COPYRIGHT AS 1100.101—1992 FIGURE 3.4 TYPICAL APPLICATION OF TYPES OF LINES—ARCHITECTURAL Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) AS 1100.101—1992 38 FIGURE 3.5 TYPICAL APPLICATION OF TYPES OF LINES—ELECTROTECHNOLOGY 3.5.6 Type G Type G lines shall be used for centre-lines and pitch lines, and for indicating features in front of a cutting plane (see Figure 3.10). They may also be used for indication of repeated details. Centre-lines of a feature should not intersect in the spaces between dashes. Centre-lines should project for a short distance beyond relevant outlines and, where necessary for dimensioning or correlation of views, they may be extended. For short centre-lines, Type G lines should be used with a long dash passing through the feature and a short dash at each end (see Figure 3.9). A Type B line may be used for a short centre-line where there is no space for a dash or where there is no confusion with other types of lines. For use of this line for developed views, see Figure 3.7. Type G lines shall be used to show material to be removed, such as locating or holding bosses and lugs which are subsequently cut off (see Figure 3.11). 3.5.7 Type H Type H lines shall be used to indicate the location of cutting planes in sectioning and the viewing position for removed views and removed partial views. The short arrowed leaders indicating direction of viewing position should be located with the arrow touching and normal to the thick ends of the Type H lines (see Figure 3.3). 3.5.8 Type J Type J lines shall be used to indicate that portion of a surface which has to comply with some special requirement. For example, Figures 3.3 and 3.12 require a surface which has to comply with some special tolerance requirement or requires special surface treatment such as surface hardening detailed by a note. 3.5.9 Type K Type K lines shall be used for the following purposes: (a) Outlines of adjacent parts (see Figures 3.3 and 3.13). Where an adjacent part is shown in section, hatching should be shown only to avoid confusion and then only along the outlines. (b) Alternative and extreme positions of movable parts (see Figure 3.3). (c) Centroidal lines (see Figure 3.18(b)). (d) Tooling outlines. Alternatively, the component outline where tool drawings are involved (see Figure 3.14). COPYRIGHT Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) 39 FIGURE 3.6 IMAGINARY INTERSECTION OF SURFACES COPYRIGHT AS 1100.101—1992 Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) AS 1100.101—1992 NOTE: 40 Section shown for hidden detail. FIGURE 3.9 HIDDEN OUTLINE TECHNIQUES COPYRIGHT Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) 41 COPYRIGHT AS 1100.101—1992 AS 1100.101—1992 42 Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) FIGURE 3.12 SURFACE TO MEET SPECIAL TOLERANCE REQUIREMENTS AND SURFACE TREATMENT FIGURE 3.13 ADJACENT PART FIGURE 3.14 TOOL SHAPE IN OUTLINE COPYRIGHT 43 AS 1100.101—1992 3.6 SPECIAL APPLICATIONS OF LINES 3.6.1 Representation of some plane faces A flat surface may be indicated by two diagonal Type B lines as shown in Figure 3.15. FIGURE 3.15 INDICATION OF FLAT SURFACES Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) 3.6.2 Representation of a rectangular opening A rectangular opening in a floor or a hatchway may be indicated by two diagonal Type B lines as shown in Figure 3.16. FIGURE 3.16 REPRESENTATION OF RECTANGULAR FLOOR OPENING 3.6.3 Partial views of symmetrical objects Where it is desired to draw a symmetrical object as a fraction of the whole, the line of symmetry shall be indicated by two short parallel Type B lines, drawn normal to and at each end of it (see Figure 3.17). 3.6.4 Other special applications Where special lines are used of types other than those shown in this Standard, their purpose should be stated. 3.7 ORDER OF PRIORITY OF COINCIDENT LINES Where two or more lines of different type coincide, the following order of priority should be observed (see Figure 3.18): (a) Visible outlines and edges. (b) Hidden outlines and edges. (c) Cutting planes. (d) Centre-lines. (e) Centroidal lines. (f) Projection lines. COPYRIGHT Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) AS 1100.101—1992 44 FIGURE 3.18 ORDER OF PRIORITY OF COINCIDENT LINES COPYRIGHT 45 AS 1100.101—1992 SECTION 4 LETTERS, NUMERALS AND SYMBOLS 4.1 LETTERS AND NUMERALS 4.1.1 Character shapes and proportions 4.1.1.1 General Characters shall be uniform and capable of being produced at reasonable speed by hand, stencil, machine, or other means. They shall remain legible and unambiguous in a direct photocopy print, in a reduced copy, and as an image on a microfilm-viewing screen. Characters shall be of simple form and preferably without serifs and other embellishments, and shall not be of exaggerated proportions. NOTE: Clarity, style, size, and spacing are important, particularly for numerals as, unlike letters, they rarely fall into self-identifying patterns and hence are read individually. 4.1.1.2 Basic form The basic form of letters and numerals should proportionally conform to those illustrated in Figures 4.1 and 4.2. 4.1.1.3 Freehand characters Although it is recognized that slight variations will naturally occur with freehand characters, the characters should as much as possible conform to the basic forms given in Figures 4.1 and 4.2. 4.1.1.4 Stencil characters Suitable stencilled characters include the following types: (a) Upright Gothic. (b) Sloping Gothic. (c) ISO 3098/1 Type B Upright. (d) ISO 3098/1 Type B Sloping. (e) Microfont. NOTES: 1 See Figures 4.1 to 4.5 inclusive. Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) 2 ISO 3098/1 Type A characters which have a height equal to 14 times the line thickness are not normally used in Australia. 4.1.1.5 Machine made characters Machine-made characters as produced by mechanical means or a transfer process should generally comply with the basic requirements specified in this Standard. 4.1.2 Height of characters The height (h) in millimetres (see Figures 4.1 to 4.5 inclusive) of characters should be one of the following: 2.5 3.5 5 7 10 14 20 NOTES: 1 For special requirements, other heights may be used, provided that the minimum height complies with the requirements of this Clause. 2 The height of lettering used for tolerances shall be the same height as the particular dimension to which they are applying. The recommended height of the characters should be not less than the height stated in Table 4.1 for the sheet sizes indicated. Where the drawing is to be reduced, the character height (h) shall be selected so that the height as reproduced is not less than 1.7 mm. TABLE 4.1 RECOMMENDED MINIMUM HEIGHT OF CHARACTERS ON DRAWINGS Character height (h), mm Sheet size Character use Titles and drawing numbers Subtitles, headings, view and section designations General notes, material lists, dimensions A0, B1 A1, A2, A3, A4 B2, B3 & B4 7 5 3.5 5 3.5 2.5 NOTE: The recommended minimum character heights are for upper-case lettering only. For upper-case and lower-case combinations, the minimum character height should be one size larger than that specified. 4.1.3 Thickness of character lines The maximum thickness of the lines used to form the characters shall be 0.1h, where h is the height of the characters as shown in Figures 4.1 and 4.2 and as specified in Clause 4.1.2. The line thickness of both lower-case and upper-case letters shall be the same (to facilitate lettering). COPYRIGHT Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) AS 1100.101—1992 46 FIGURE 4.2 SLOPING GOTHIC (ITALIC) CHARACTERS COPYRIGHT Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) 47 * AS 1100.101—1992 Either of these characters is acceptable by ISO, but ‘a’ and ‘7’ are not recommended for use in Australia. FIGURE 4.3 ISO 3098/1 TYPE B UPRIGHT CHARACTERS 4.1.4 Spacing 4.1.4.1 Spacing of characters Characters forming a word or a number should be spaced so that the distance between the characters (see Figure 4.6) is approximately twice the thickness of the line forming such characters or 1 mm, whichever is the greater. Numerical values shall be expressed in accordance with AS 1000. 4.1.4.2 Space between words The space between words shall be not less than 0.6h and should be not more than 2h. 4.1.4.3 Space between lines of lettering The space between lines of lettering shall be not less than 0.6h. 4.1.5 Use of characters Only one style of character should be used generally throughout a drawing. Vertical characters should be used for titles, drawing numbers, and reference numbers. Upper-case letters should be used. Lower-case letters shall be used for conventional signs and symbols normally requiring such characters, e.g. mm, kg, kPa. Underlined lettering should be avoided. Special emphasis, where required, may be given by the use of larger characters, or a change of style. Where necessary for clarity or to prevent misinterpretation between upper-case ‘I’ and lower-case ‘l’ and the numeral ‘1’, serifs may be added. The letters ‘O’ and ‘I’ should not be used in combination with numbering owing to the liability of confusion with the numerals ‘0’ and ‘1’. All characters in a drawing shall be kept clear of lines. NOTE: Where a line precludes this requirement, the line may be interrupted sufficiently to accommodate characters (see Figure 4.7). COPYRIGHT Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) AS 1100.101—1992 48 FIGURE 4.5 MICROFONT CHARACTERS COPYRIGHT Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) 49 AS 1100.101—1992 FIGURE 4.7 CHARACTERS CLEAR OF LINES 4.1.6 Decimal form 4.1.6.1 Decimal sign The decimal sign for technical drawings and associated documents should be the dot, either on the line or at midheight. An example is shown in Figure 4.8. The diameter of the dot should be twice the thickness of the line used to form the character, and shall be not less than the line thickness. It should be given a full character space. NOTES: 1 The preferred location of the dot is on the line. 2 The decimal comma is commonly used in some countries. 4.1.6.2 Decimal fractions Where the quantity is less than unity, the decimal sign shall be preceded by zero (0) (see Figure 4.8). 0.45 FIGURE 4.8 EXAMPLE OF DECIMAL FRACTION COPYRIGHT AS 1100.101—1992 50 4.1.7 Vulgar fractions The minimum height of the numerator and denominator of a vulgar fraction shall be as given in Clause 4.1.2, and should be separated by a horizontal line. Where space is limited, a sloping line may be used. 4.2 ITEM REFERENCES 4.2.1 General Item references shall be assigned in sequential order to each component part shown in assembly or detailed item on the drawing. Identical parts shown on the same drawing shall have the same item reference. Item references shall be cross-referenced to an item list giving the appropriate information of the items concerned. Each complete subassembly to be incorporated in the assembly shown on the drawing may be identified by one item reference. 4.2.2 Terminology 4.2.2.1 Item—a non-specific term used to denote a unit of product including materials, parts, assemblies, structures, equipment, accessories and attachments. 4.2.2.2 Reference (item) number—a number assigned to an item or detail on a drawing for the purpose of cross-referencing to another drawing or a parts list, item list, or item description. Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) NOTE: For electrotechnology item designation, see AS 3702. 4.2.3 Use Item references should generally be composed of Arabic figures only. They may be augmented by capital letters when necessary. Item references on any one drawing shall have the same height of lettering. They shall be clearly distinguished from all other indications by— (a) being double the height of those other indications; or (b) being enclosed in circles having the same diameter (see Figure 4.10). Where the relation between the item reference and its associated item is not obvious, the connection between them should be shown by a leader line. Leader lines shall not intersect. They should be kept as short as practicable and generally they should be drawn at an angle to the item reference. The leader line for circled item references shall be directed towards the centre of the circle (see Figure 4.10). For the sake of clarity and legibility of the drawing, item references should be arranged in vertical columns or horizontal rows (see Figure 4.9). Item references of related items may be shown against the same leader line, e.g. bolt, nut and washer (see Figure 4.9, Items 8, 9 and 10). Item references of identical items should only be shown once, except in special cases such as complicated assembly where for clarity such references may be shown more than once. It is also recommended to arrange, as far as possible, the item references on the drawing in such a way as to facilitate their identification (see Figure 4.9). 4.3 SYMBOLS AND TERMINATORS 4.3.1 General Where symbols and terminators are used in technical drawings, the size of characters and the spacing of lines and characters shall comply with this Section together with Section 3. A comparison of the symbols used by ISO and those adopted by Australian and other national Standards bodies is given in Appendix A. 4.3.2 Terminology 4.3.2.1 Symbol—a mark, character, letter or combination thereof which is accepted for indicating an object, idea or process. NOTES: 1 This applies particularly to SI units and their multiples, chemical elements, letter symbols for quantities, mathematical signs, and the like. 2 Letter symbols are the same in the plural as in the singular. 4.3.2.2 Terminator—a mark or character used for terminating leaders and dimension lines. 4.3.3 Arrowheads Arrowheads shall be well defined. They may be open or solid and should comply with the forms and proportions shown in Figure 4.11. The length should be from 3 mm to 5 mm. 4.3.4 Dots 4.3.4.1 Dots terminating line Dots used for terminating dimension lines shall be of a diameter that is approximately 3 times the thickness of the dimension line which they terminate, but not less than 1.5 mm. 4.3.4.2 Dots terminating leaders Dots used for terminating leaders shall be of a diameter that is approximately twice the thickness of the leaders which they terminate, but not less than 1 mm. 4.3.4.3 Dots used as decimal signs See Clause 4.1.6.1. COPYRIGHT Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) 51 FIGURE 4.10 NUMBERS FOR REFERRING TO ITEM LISTS COPYRIGHT AS 1100.101—1992 AS 1100.101—1992 52 FIGURE 4.11 ARROWHEADS 4.3.4.4 Use of arrowheads and dots In drawings of individual items, leaders from notes should terminate in arrowheads; however, in assembly drawings dots are preferred for the termination of leaders from notes and item numbers. Such dots should be within the outline of the items (see Figures 4.12 and 4.13). Where arrowheads are used to terminate leaders, the point of the arrowhead should touch the first point of reference belonging to the particular item as illustrated in Figure 4.13, thus avoiding any misinterpretation where an outline is common to more than one item, e.g. that common to Items 8 and 9, and that common to Items 9 and 10 in Figure 4.13. On any one drawing, all leaders should have the same terminator, i.e. either dots or arrowheads. NOTE: For arrowheads used to show direction of viewing, see Section 6. Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) 4.3.4.5 Slashes Slashes may be used on dimension lines in place of arrowheads, e.g. on architectural drawings, but slashes are not preferred. FIGURE 4.12 LEADERS TERMINATING IN DOTS WITHIN THE OUTLINES OF THE OBJECTS COPYRIGHT 53 AS 1100.101—1992 Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) FIGURE 4.13 LEADERS TERMINATING IN ARROWHEADS TOUCHING OUTLINES 4.3.4.6 Dimensioning and tolerancing Symbols used for dimensioning and tolerancing and their applications are shown in Figure 4.14. The dimensions of these symbols for the various values of the character height h are given in Table 4.2. Definitions of tolerancing symbols are given in Section 8. 4.3.4.7 Graphical symbols For the shape and proportion of graphical symbols used in general engineering and electrotechnology, refer to the appropriate Standards. 4.3.4.8 Use of notes to supplement symbols Situations may arise where the desired geometric requirement cannot be completely conveyed by the symbols described. In such cases, a note may be used to describe the requirement, either separately or supplementing a geometric tolerance. TABLE 4.2 DIMENSIONS OF SYMBOLS FOR DIMENSIONING AND TOLERANCING millimetres h 0.5h 0.7h 1.4h 2h 2.5h 2.8h 3h 2.5 3.5 5.0 7.0 10 14 20 1.3 1.8 2.5 3.5 5.0 7.0 10 1.8 2.5 3.5 5.0 7.0 10 14 3.5 5.0 7.0 10 14 20 28 5.0 7.0 10 14 20 28 40 6.3 8.8 12.5 17.5 25 35 50 7.0 10 14 20 28 40 56 7.5 10.5 15 21 30 42 60 LEGEND: h = character height. COPYRIGHT Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) AS 1100.101—1992 54 NOTE: Sloping lines are at 60 degrees to the horizontal unless otherwise indicated. FIGURE 4.14 SHAPE AND SIZE OF SYMBOLS COPYRIGHT 55 AS 1100.101—1992 SECTION 5 SCALES 5.1 GENERAL Many technical drawings are drawn to scale. The scale to be chosen for a drawing shall permit easy and clear interpretation of the information depicted. 5.2 TERMINOLOGY 5.2.1 Scale—the ratio of the linear dimension of an element of an object as represented in the drawing to the linear dimension of the same element of the object itself. Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) 5.3 INDICATION OF SCALES 5.3.1 Methods The complete designation of a scale on a drawing shall be by one of the following methods: (a) A ratio prefixed by the word ‘SCALE’, e.g. ‘SCALE 1:100’. (b) A block or graduated scale, e.g. (c) Where the drawing is not drawn to scale, a note ‘NOT TO SCALE’ or a diagonal line drawn through the space reserved for the scale ratio. Where a drawing has no scale, a scale notation is unnecessary, e.g. a circuit diagram. 5.3.2 Single scale Where only one scale is used in a drawing, it should be indicated in or near the title block. 5.3.3 Multiple scales Where one scale predominates, the indication of that scale should be shown in or near the title block together with ‘OR AS SHOWN’, and other scales should be indicated adjacent to the view or views concerned. Where more than one scale is used in a drawing, the scales shall be clearly shown adjacent to the view or views concerned. A notation ‘SCALES AS SHOWN’ should also be indicated in or near the title block. Where different scales are used for horizontal and vertical dimensions, such as in road profiles, each scale should be clearly indicated on the drawing sheet, e.g. HORIZONTAL SCALE 1:500 VERTICAL SCALE 1:100 5.4 SCALE RATIOS 5.4.1 Engineering and architectural drawing scales The recommended scales for use in engineering drawing practice and in architectural and building drawings are specified in Table 5.1. TABLE 5.1 ENGINEERING AND ARCHITECTURAL DRAWING SCALES Category Enlargement scales Recommended scales 50:1 5:1 20:1 2:1 Full size Reduction scales 10:1 1:1 1:2 1:20 1:200 1:2 000 1:5 1:50 1:500 1:5 000 1:10 1:100 1:1 000 1:10 000 NOTE: If, for special applications, there is need for a larger enlargement scale or a smaller reduction scale than those shown in the table, the recommended range of scales may be extended in either direction, provided that the required scale is derived from a recommended scale by multiplying by integral powers of 10. In exceptional cases where for functional reasons the recommended scales cannot be applied, intermediate scales may be chosen. 5.4.2 Surveying and mapping scales The recommended scales for surveying and mapping purposes are specified in Table 5.2. In addition the following surveying and mapping scales are currently in use and are acceptable for special purposes in certain areas: 1:125 1:400 1:750 1:800 1:1 250 1:3 000 1:4 000 1:8 000 1:12 500 COPYRIGHT AS 1100.101—1992 56 TABLE 5.2 SURVEYING AND MAPPING SCALES Reduction ratios 1:2 00 1:2 000 1:250 1:2 500 1:25 000 1:250 000 1:50 1:500 1:5 000 1:50 000 1:500 000 1:100 1:1 000 1:10 000 1:100 000 1:1 000 000 Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) 5.5 LARGE SCALE DRAWINGS It is recommended that, for information, a full size view be added to the large scale representation of a small object. The full size view may be simplified by showing the outlines of the object only. COPYRIGHT 57 AS 1100.101—1992 SECTION 6 PROJECTIONS Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) 6.1 IDENTIFICATION Features, cutting planes, sectional views, sections and special views should be identified by letters of the alphabet according to the following rules: (a) Letters I, O, and Q shall not be used. (b) When the other 23 letters have been exhausted, combinations of 2 letters shall be used, e.g. AA, AB, AC. (c) Letters or letter combinations shall be used only once on any drawing, irrespective of the purpose; e.g. if ‘A’ is used to designate a view, it shall not be used on a feature, cutting plane, sectional view or section. (d) Identifying letters or letter combinations for cutting planes shall be applied at each end of such planes, and in the corresponding notes for sectional views and sections the same identifying letters or letter combinations shall be used separated by a hyphen, e.g. SECTION A-A, SECTION B-B, SECTION AB-AB. Views shall be designated as shown in Figure 6.1. View View View View View View in in in in in in direction direction direction direction direction direction A is designated: FRONT VIEW B is designated: TOP VIEW C is designated: LEFT SIDE VIEW D is designated: RIGHT SIDE VIEW E is designated: BOTTOM VIEW F is designated: REAR VIEW FIGURE 6.1 DESIGNATION OF VIEWS 6.1.1 Views 6.1.1.1 Top view (plan)—the horizontal section or projection of any object, such as a building, or the projection on a horizontal plane of a site, building or component, viewed from above at right angles to the plane of section or projection. 6.1.1.2 Side, front and rear view (elevation)—the projection on a vertical plane of any object, such as a building or component viewed at right angles to the plane of projection. COPYRIGHT AS 1100.101—1992 58 6.2 TYPES OF PROJECTION A drawing of a component, assembly, structure, or part thereof shall be drawn using one or more of the projection methods shown in Table 6.1. TABLE 6.1 METHODS OF PROJECTION Distinctive feature Parallel lines of sight Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) Converging lines of sight Projection type Generic Application Particular Orthogonal Third angle (preferred) First angle Axonometric Isometric Dimetric Trimetric Oblique Cavalier Cabinet General Perspective One-point (parallel) Two-point (angular) Three-point (oblique) Two-dimensional multiview drawings Three-dimensional single-view ‘pictorial drawings’ 6.3 ORTHOGONAL PROJECTION 6.3.1 Terminology—Orthogonal projection The projection of an object in which the line of sight is perpendicular to the plane of projection. Figure 6.2 illustrates the derivation of the terms ‘First Angle Projection’ and ‘Third Angle Projection’, as applied to orthogonal projection. 6.3.2 General Third angle projection is the formation of an image of a view upon a plane of projection placed between the object and the observer. First angle projection places the object between the observer and the plane of projection. FIGURE 6.2 ORTHOGONAL PROJECTION COPYRIGHT 59 AS 1100.101—1992 Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) 6.3.3 Methods The two methods of orthogonal projection in use, known as ‘third angle and first angle’, are as follows: (a) Third angle projection Each view is placed so that it represents the side of the object near to it in the adjacent view (see Figure 6.3). (b) First angle projection Each view is placed so that it represents the side of the object remote from it in the adjacent view (see Figure 6.4). The third angle method of projection is preferred. All drawings in this Standard are third angle unless otherwise stated. The drawings shall be marked to indicate the method of projection (see Clause 2.5.6). The directions in which the views are taken should be clearly indicated. COPYRIGHT AS 1100.101—1992 60 6.3.4 Selection of views 6.3.4.1 Principle of selection Views shall be selected according to the following principles: (a) To reduce the number of views required to fully delineate the information to be specified. (b) To avoid the need for hidden outlines. (c) To avoid unnecessary repetition of detail. 6.3.4.2 Disposition and number of views The normal disposition of views in third angle projections is shown in Figure 6.3 and that in first angle projection is shown in Figure 6.4. The number of views drawn shall be sufficient to portray the shape of the object without possibility of misinterpretation. For many objects three views are sufficient. Any three adjacent views may be used. NOTE: The views of Figures 6.3 and 6.4 do not necessarily define completely all features of an object. Full definition may require the application of other following clauses, the use of notes and sometimes, the use of sections. Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) Some objects may, however, be completely represented by less than three views where the information, which would have been given by the omitted views, is supplied by notes or other means. For example, some objects may be represented adequately even by one view if the necessary dimensions are suitably indicated (see Figure 6.5). 6.3.5 Deviation from method of projection Views deviating from the method of projection being used on a drawing shall be adequately titled. The use of sections instead of an outside view may obviate the need for deviation. The direction in which the object is viewed shall be indicated by an arrow approximately twice the size of those used to terminate dimensions, and letters one size larger than the characters used in dimensions and notes. See Figure 6.6. FIGURE 6.5 SINGLE VIEW DRAWINGS SUITABLY DIMENSIONED COPYRIGHT 61 AS 1100.101—1992 Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) FIGURE 6.6 INDICATION OF VIEW DEVIATING FROM METHOD OF PROJECTION 6.3.6 Partial views Partial views may be used where full views do not improve the full delineation of the information to be specified. The partial view shall be cut off by a continuous thin freehand line (Type C) or straight lines with zig-zags (Type D). The principle of partial views may also be applied to auxiliary views (see Clause 6.3.7). Examples of partial views are shown in Figure 6.7. FIGURE 6.7 EXAMPLES OF PARTIAL VIEWS COPYRIGHT AS 1100.101—1992 62 Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) 6.3.7 Auxiliary views Objects having inclined faces may have such faces projected to show the true shape of the inclined surface. The view is obtained by looking perpendicularly at the inclined face and projecting a true shape view of it on to an auxiliary plane perpendicular to the line of sight. Auxiliary views should be drawn in third angle projection, irrespective of the method of projection used throughout the particular drawing. Examples of auxiliary views are shown in Figure 6.8 where (a) is a normal (perpendicular) auxiliary view and (b) is a removed auxiliary view. In the latter example, the removed view shall be identified and the direction of viewing shall be indicated. Its orientation should not be changed, but if this is also necessary, the number of degrees through which it is rotated should be stated, as in Figure 6.8(c). 6.3.8 Removed views and details Removed views (details) are auxiliary views removed from their true projected positions in order to provide added clarity. They may be drawn as full or partial views and the scale may be the same as that of the main view or larger. Removed views to the same scale shall be identified and the direction of viewing shall be indicated by letter(s) (see Figure 6.8 and Clause 7.4.8). The element of the actual view of the object to which the removed view applies may be indicated by a circle or a rectangle drawn with a Type B line (see details on Figure 6.9). Removed views to a larger scale shall be identified and the scale ratio shown. If the removed view is close to the element of the actual view, the circle or rectangle may be linked to the indicator by a leader (see details on Figure 6.9(b)). 6.3.9 Rounded and filleted intersections Intersections between surfaces are often required to be rounded or filleted. An intersection of this nature, which theoretically shows no line, may be indicated by a conventional line, the location of which should be at the intersection of the principal surfaces disregarding the fillet or round. The contour shall be shown as illustrated in Figures 6.10 and 6.11 (see also Figure 3.6). 6.3.10 Views of symmetrical parts To save time and space, symmetrical objects may be drawn as a fraction of the whole (see Figure 6.12). The line of symmetry is identified at its ends by two thin short parallel lines drawn at right angles to it (see Figure 6.12(a), (b), and (d)). Another method is to show the lines representing the object extending a little beyond the line of symmetry (see Figure 6.12(c)). In this case, the short parallel lines may be omitted. NOTE: In the application of this practice, it is essential that due care is taken to avoid loss of understanding of the drawing. 6.3.11 Simplified representation of repetitive features simplified as permitted by Clause 9.3.1. The presentation of repetitive features may be 6.4 SPATIAL GEOMETRY 6.4.1 Terminology Spatial geometry, or descriptive geometry, is the technique of solving three-dimensional problems by orthogonal projection onto perpendicular planes. 6.4.2 The coordinate system The coordinate system is used to represent the location of a point in space by the use of three axes, viz x, y and z, with associated unit scales. The axes of the coordinate system are each orthogonal, with their relative orientation shown in Figure 6.13(a). The positive and negative direction on each axis are shown in Figure 6.13(b). The top view of the coordinate axes shall be used to represent unit dimensions on two axes only (see Figure 6.13(c)). Lower-case italics shall be used to represent the position of a point in two dimensions. In this case the identification of the z-axis is omitted. This top view is used to describe points involving two dimensions. The unit values for the x, y, and z axes respectively shall be used to specify the coordinates for points in three-dimensional space. The projection of a point A shall be as shown in Figure 6.14. For working with two principal axes only to describe the position of a point, the unit values in x and y directions shall be specified for the point which is (x,y), as illustrated in Figure 6.15. 6.4.3 Principal planes Two perpendicular principal planes may be positioned relative to a point, line, plane, solid, or set of coordinate axes to provide viewing and reference planes for orthogonal projection. The two principal planes shall be designated the ‘principal horizontal plane’ and ‘principal vertical plane’, or xy and xz reference planes respectively, as appropriate to the application. The projection of the principal trace(s) and points in a plane in two-dimensional space is shown in Figure 6.16. Principal planes may be positioned relative to the coordinate reference axes x, y, and z, so that two of the reference axes are parallel to one of the principal planes (see Figure 6.17). There is no restriction, upon the arrangement of principal planes relative to points, lines, and solids. COPYRIGHT Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) 63 FIGURE 6.8 AUXILIARY VIEWS COPYRIGHT AS 1100.101—1992 Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) AS 1100.101—1992 64 FIGURE 6.9 REMOVED VIEWS COPYRIGHT 65 AS 1100.101—1992 Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) FIGURE 6.10 ROUNDED CORNERS AND FILLETS 6.4.4 Notation of principal planes and points Notation identifying planes, lines and points may be used to solve complex problems. The convention shall be as follows: (a) The principal horizontal plane shall be represented by the letter H. (b) The principal vertical plane shall be represented by the letter V. (c) Lines and points shall be represented by alphanumeric symbols, using upper-case letters for points on a pictorial view, and lower-case for points on a projected view (see Figure 6.18(a) and (b)). (d) Where appropriate, subscripts shall be used to distinguish between two or more projections of a point (see Figure 6.18(c)). (e) Where the projection of two or more points coincide, notation of the projected point(s) closest to the direction of view shall take precedence (see Figure 6.18(c), projections to points av ev and bvdv). 6.4.5 Auxiliary planes of projection The intersection of two planes is known as a trace. Traces of principal planes shall be represented by a Type B line (see Figure 6.19). For the special case of cutting planes, see Clause 6.4.6. Traces of auxiliary planes shall be identified by upper-case letters according to the reference planes which have been intersected, and in accordance with the sequence of these intersections (see Figure 6.20). 6.4.6 Cutting planes Cutting planes shall be represented by a Type H line. Figure 6.21 illustrates the cutting of a solid by an auxiliary plane, simply inclined to the principal horizontal plane. The portion nearest the plane of projection shall be shown removed in the adjacent view. When the true shape of sections are projected, they shall not be hatched. 6.5 AXONOMETRIC PROJECTION 6.5.1 Terminology—Axonometric projection—the projection of an object in which the lines of sight are perpendicular to the plane of projection and where the object is orientated so that its three principal axes are all inclined to the plane of projection (see Figure 6.22). 6.5.2 Methods There are three methods of axonometric projection as follows: (a) Isometric—where the three angles between the projections of the three principal axes of the object on the plane of projection form equal angles of 120°. (b) Dimetric—where two of the angles between the projections of the three principal axes of the object on the plane of projection form equal angles and the third angle is different. (c) Trimetric—where the angles between the projections of the three principal axes of the object on the plane of projection form unequal angles. Isometric projection is recommended for depicting objects having characteristic features in all directions; dimetric and trimetric projections are recommended for depicting objects having characteristic features in two directions. COPYRIGHT Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) AS 1100.101—1992 66 FIGURE 6.11 ROUNDED AND FILLETED INTERSECTIONS COPYRIGHT Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) 67 COPYRIGHT AS 1100.101—1992 FIGURE 6.12 SYMMETRICAL PARTS—OMISSION OF UNNECESSARY DETAIL Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) AS 1100.101—1992 68 FIGURE 6.14 ILLUSTRATION AND PREFERRED NOTATION OF A POINT IN THREE DIMENSIONS FIGURE 6.15 ILLUSTRATION OF PREFERRED NOTATION OF THE PROJECTION OF A POINT IN TWO DIMENSIONS COPYRIGHT Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) 69 FIGURE 6.17 USUAL POSITIONING OF PRINCIPAL PLANES RELATIVE TO THE COORDINATE AXES COPYRIGHT AS 1100.101—1992 Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) AS 1100.101—1992 70 FIGURE 6.19 REPRESENTATIONS OF INCLINED PLANES COPYRIGHT Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) 71 AS 1100.101—1992 FIGURE 6.21 PICTORIAL AND ORTHOGONAL REPRESENTATIONS OF A SOLID CUT BY SIMPLY INCLINED PLANE COPYRIGHT AS 1100.101—1992 72 Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) FIGURE 6.22 AXONOMETRIC PROJECTION 6.5.3 Choice of axes 6.5.3.1 One principal axis The axes may be placed in a variety of positions. By convention the projection of one of the principal axes of the object is selected as a vertical axis. 6.5.3.2 Other principal axes Other principal axes are placed as follows: (a) Isometric projection The other two principal axes are fixed by definition. (b) Dimetric and trimetric projection It is recommended that in order to avoid the appearance of distortion on large flat areas, the angle which that face makes with the plane of projection should be increased. It is also recommended that for more important faces of objects where details must be shown more clearly, the angle between that face and the plane of projection should be decreased. Figure 6.23(b) shows an improvement resulting from an increase in this angle because— (i) the horizontal plane is less distorted; and (ii) the vertical face is shown more clearly and with more detail. Dimetric drawings may be orientated with the equal angles disposed on either side of any principal axis. 6.5.4 Examples and guidelines 6.5.4.1 Isometric drawing Figure 6.24 illustrates a typical isometric drawing of an object. Lengths parallel to the principal axes shall be drawn in true length to any selected scale, i.e. the ratio of equal lengths on the axes shall be— x:y:z = 1:1:1 NOTES: 1 The true axonometric projection of an object orientated as defined in Clause 6.5.1(a) is an isometric projection, and will be smaller than an isometric drawing of the object because the scales parallel to all three axes are foreshortened in projection in the ratio 2: 3, i.e. 0.816:1 approximately. 2 For information on the representation of circles in isometric projection, see Appendix C. 6.5.4.2 Dimetric drawing Figure 6.25 is a typical dimetric drawing of the same object as in Figure 6.24. Lengths parallel to the two principal axes shall be drawn in true length to any selected identical scale. Lengths parallel to the third principal axis will be a different scale depending on the selected orientation. For convenience, the ratio of equal lengths on the axes is selected so that— x:y:z = 1:1:0.5 (See Appendix C) NOTES: 1 For information on the representation of circles in dimetric projection and special aids, see Appendix C. 2 In many cases when the angle α is small, such as in Figure 6.25, a circle is sufficiently accurate instead of an ellipse in the segment xy or in planes parallel thereto. COPYRIGHT Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) 73 FIGURE 6.24 ISOMETRIC DRAWING COPYRIGHT AS 1100.101—1992 Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) AS 1100.101—1992 74 FIGURE 6.25 DIMETRIC DRAWING 6.5.4.3 Trimetric drawing Figure 6.26 illustrates a typical trimetric drawing of the same object as in Figure 6.24. The length parallel to one selected principal axis shall be in true length to any selected scale. Lengths parallel to the other principal axes will be to two different scales resulting from the selected orientation. NOTE: For information on special scales for use with trimetric projections, see Appendix C. 6.6 OBLIQUE PROJECTION 6.6.1 Terminology—Oblique projection—the projection of an object in which the lines of sight are parallel to each other but inclined to the plane of projection where the object is orientated with the principal face parallel to the plane of projection, thus making this face and parallel faces show in true shape. (See Figure 6.27.) 6.6.2 Methods There are three methods of oblique projection, each dependent on the comparative scales of the front axes and the receding axis, as follows: (a) Cavalier—the lines of sight make an angle of 45° with the plane of projection. The same scale is used on all axes. Figure 6.28 is an example of this type of projection. (b) Cabinet—the lines of sight make an angle of 63°26’ with the plane of projection. The scale on the receding axis is one-half of the scale on the other axes. Figure 6.29 shows an example of this type of projection. (c) General oblique—the lines of sight make any angle other than 45° or 63°26’ with the plane of projection. For practical purposes, the angle should lie between 45° and 60°; under these conditions, the scale on the receding axis will be between 1 and 0.5 times the common scale of the other axes. Figure 6.30 shows an example of this type of projection. The projection of the receding axis on the plane of projection may be at any angle to the horizontal. For convenience, an angle of 30°, 45°, or 60° is recommended. NOTE: For information on the effect of the angle of the lines of sight, see Appendix D. 6.6.3 Choice of method and orientation Cylinders and cones should have their axes on the receding axis to reduce distortion and to make it possible to draw circles in true shape. Distortion may be decreased by reducing the scale of the receding axis. COPYRIGHT Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) 75 FIGURE 6.27 OBLIQUE PROJECTION COPYRIGHT AS 1100.101—1992 Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) AS 1100.101—1992 76 FIGURE 6.29 OBLIQUE PROJECTION—CABINET TYPE COPYRIGHT Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) 77 AS 1100.101—1992 FIGURE 6.30 OBLIQUE PROJECTION—GENERAL 6.7 PERSPECTIVE PROJECTION 6.7.1 Terminology—Perspective projection—the projection of an object in which thelines of sight converge to a point of sight located so that the projection plane is between the object and the observer. (See Figure 6.31.) FIGURE 6.31 PERSPECTIVE PROJECTION 6.7.2 Methods There are three methods of perspective drawings, each dependent on the orientation of the object to the plane of projection, as follows: (a) One-point perspective or parallel—two of the principal axes of the object are parallel to the plane of projection and the third, therefore, is perpendicular to the plane of projection. COPYRIGHT AS 1100.101—1992 78 (b) Two-point perspective or angular—one of the principal axes (usually a vertical axis) is parallel to the plane of projection, and the other axes are inclined thereto. (c) Three-point perspective or oblique—all three principal axes are inclined to the plane of projection. NOTES: 1 The only features that can be readily scaled are those of the object that actually lie on the plane of projection. 2 The plane of projection is also known as the picture plane (see Figure 6.32). Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) 6.7.3 Examples and guidelines Figure 6.32 illustrates the general principles of perspective views. (The example shown is a two-point perspective.) Figure 6.33 illustrates the three types of perspective drawings. It is recommended that the point of sight should be located so that the cone of rays having its apex at the point of sight and including the entire object, has an angle at the apex not greater than 30°. Perspective drawings may be conveniently produced by photographic methods and grids. For architectural and CAD work where the object is close to the horizon, it is recommended that— (a) a greater angle be used; (b) the point of sight be located centrally in front of the object; and (c) the point of sight be located at sufficient height to show the desired amount of detail on the horizontal surfaces. FIGURE 6.32 GENERAL PRINCIPLES OF PERSPECTIVE PROJECTION COPYRIGHT Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) 79 FIGURE 6.33 PERSPECTIVE DRAWING COPYRIGHT AS 1100.101—1992 AS 1100.101—1992 80 6.8 OTHER DETAILS—PICTORIAL DRAWINGS 6.8.1 Sectioned views Section planes should pass through centre-lines and should be parallel to one or more of the principal planes of the object (see examples in Figure 6.34). Hatching of half-sections should be drawn in such directions that they would appear to coincide at the planes when folded together as illustrated in Figure 6.34(b). FIGURE 6.34 SECTIONAL VIEWS AND HATCHING Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) 6.8.2 Fillets and rounds Fillets and rounded edges may be emphasized by means of straight or curved lines as illustrated in Figure 6.35. FIGURE 6.35 6.8.3 Intersections FILLETS AND ROUNDS Intersections should be drawn correctly and shown by lines as illustrated in Figure 6.36. FIGURE 6.36 INTERSECTIONS COPYRIGHT 81 AS 1100.101—1992 6.8.4 Screw threads Screw threads may be represented by a series of ellipses or circles uniformly spaced along the centre-line of the thread. Screw threads should be evenly spread, but it is not necessary to reproduce the actual pitch (see example in Figure 6.37). Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) FIGURE 6.37 REPRESENTATION OF THREADS 6.8.5 Dimensioning Drawings shall be dimensioned where required by the same general methods as for orthogonal projections, although the scales vary with the method of projection used. Each dimension line, the associated projection lines and the line being dimensioned shall lie in the same plane, as illustrated in Figure 6.38. Dimensions shall be inserted by one of the following methods: (a) Unidirectional—when all letters and numerals are read from the bottom of the drawing, as illustrated in Figure 6.38(a). (b) Pictorial plane dimensioning—where all letters and numerals lie in one of the principal planes, as illustrated in Figure 6.38(b). FIGURE 6.38 DIMENSIONING COPYRIGHT AS 1100.101—1992 82 SECTION 7 SECTIONS Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) 7.1 GENERAL 7.1.1 Terminology—Section—the view of an object at the cutting plane which may typically include that detail beyond the cutting plane. (See Figure 7.1.) 7.1.2 Method of indicating sections Sections are generally indicated by hatching of cut surfaces and a label as detailed in this Section. 7.2 CUTTING PLANES 7.2.1 Selection Cutting planes should be selected to pass through the principal features of the object, and preferably be shown through an external view and not through a section. Where the cutting plane is taken through a section, the resulting section should be drawn as if the original section was a full view. 7.2.2 Indication—General Except where otherwise specified below, cutting planes shall be indicated by Type H lines drawn right across the object. The direction of viewing shall be indicated by arrowheads, and identifying letters as specified in Clause 6.1 shall be placed adjacent to the tail of arrows (see Figure 7.1). FIGURE 7.1 SECTIONS 7.2.3 Indication—Other methods Where clarity is not impaired, the cutting plane line may be simplified as illustrated in Figure 7.2. A typical method of indicating sections in architectural and structural drawings is illustrated in Figure 7.3. COPYRIGHT 83 AS 1100.101—1992 FIGURE 7.2 SIMPLIFIED INDICATION OF CUTTING PLANE Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) Where the cutting plane is a principal plane of symmetry, the indication, other than a centre-line, may be omitted as shown in Figure 7.4. Where only one cutting plane is involved on a drawing, the identifying letters may be omitted. Where the resulting sections or sectional views are symmetrical or are drawn in correct projection as indicated on the drawing, the arrowheads may be omitted (see Figure 7.18(a)). 7.3 HATCHING 7.3.1 Single part The cut or broken surface of sections shall be indicated by hatching except where the intent of the drawing is clear without it and where indicated in Clause 7.3.5. It is recommended that as far as practicable, hatching should consist of a series of equally spaced Type B parallel lines drawn at 45° approximately to the edge of the drawing sheet, as illustrated in Figure 7.5(a). If the shape or position of the part is such that 45° hatching would be parallel to one of the sides, another angle may be chosen, as illustrated in Figure 7.5(b). The lines should be suitably spaced in relation to the area to be covered. Provided that there is no loss of clarity, wide spacing is recommended. Sectioning of different areas of the same part shall have hatching at the same angle and spacing (see Figure 7.18). Methods of identifying particular materials by hatching, on architectural and structural drawings, are shown in AS 1100.301 and AS 1100.501. 7.3.2 Adjacent parts Where two adjacent parts in an assembly are sectioned, the hatching on each part should be at different angles, normally mutually at right angles, as illustrated in Figure 7.6(a). Where more than two adjacent parts in an assembly are sectioned, and it is necessary to clearly distinguish them, such distinction may be made by varying the spacing of the hatching or by the use of angles other than 45° (see Figure 7.6(b) and (c)). 7.3.3 Existing adjacent part Where it is necessary to show a section of an existing adjacent part, hatching should be shown only to avoid confusion, and then only along the outlines. 7.3.4 Large areas Where large areas of sectioned material have to be shown, especially those hatched freehand, such as concrete, earth, rock, it is recommended that only the edges be sectioned, as indicated in Figure 7.7. 7.3.5 Interruption for lettering and numerals Interruptions for lettering and numerals shall be carried out in accordance with Figure 4.7 and Figure 7.8. 7.3.6 Thin areas Areas in sections which by virtue of the scale of the drawing are too thin for normal hatching such as structural shapes, sheet metal, packing, gaskets, damp courses and electrical insulation, shall be filled in solid, as illustrated in Figure 7.9. Where adjacent areas are similarly treated, a thin space of not less than 1 mm shall be left between them. 7.3.7 Offset, contiguous, discontiguous, or curved sectioning In order to include features which are not in a true plane, the cutting plane may be offset or curved so as to include several lines or curved surfaces. Discontinuities on cutting planes should not be indicated in section. Where the cutting plane is discontinuous or curved, the hatching should be continuous (see Figure 7.10). COPYRIGHT Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) AS 1100.101—1992 84 FIGURE 7.3 ALTERNATIVE METHOD INDICATING A CUTTING PLANE COPYRIGHT Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) 85 FIGURE 7.6 HATCHING OF ADJACENT PARTS COPYRIGHT AS 1100.101—1992 Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) AS 1100.101—1992 86 FIGURE 7.9 HATCHING AS SOLID AREA COPYRIGHT 87 AS 1100.101—1992 Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) FIGURE 7.10 CONTINUITY OF HATCHING 7.4 SECTIONS 7.4.1 General Sectional views should be orientated as for normal views in third angle projection (or first angle as appropriate). See Figure 7.1. Each sectional view or section shall be identified with its appropriate cutting plane, where identified, by inscribing a subtitle below the view or section; e.g. ‘SECTION A-A’, ‘SECTION B-B’. See Figures 7.1 and 7.13. Where clarity is not impaired, either the subtitles SECTION or SECTION A-A may be omitted. See Figures 7.4, 7.17 and 7.18. All hidden outlines in the section should be omitted except in special cases (see Figure 7.13). 7.4.2 Full sections Where the cutting planes extend right across the object as in Figure 7.1, a full section is obtained. 7.4.3 Half sections Objects which are symmetrical about a centre-line may be drawn having one half in outside view and the other half as a section as illustrated in Figure 7.11. FIGURE 7.11 HALF SECTION COPYRIGHT AS 1100.101—1992 88 7.4.4 Local or part sections Local or part sections may be taken at convenient places on the actual view of the object to show hidden detail, the boundary of such sections being shown by a Type C line, as illustrated in Figure 7.12 (see also Figure 3.8). Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) FIGURE 7.12 LOCAL OR PART SECTION 7.4.5 Aligned sections Aligned sections are the result of using discontinuous or curved cutting planes as stated in Clause 7.3.7 where the ends of the cutting plane are not parallel. In these cases, the non-parallel plane shall be revolved into the plane of projection. Figure 7.13 shows examples of an aligned section A-A and an auxiliary aligned section B-B. 7.4.6 Revolved sections Revolved sections show the shape of the cross-section in the actual view of the object, the cutting plane being revolved in position, as illustrated in Figure 7.14. The outline of a revolved section shall be a thin line, i.e. Type B. Further identification is unnecessary. 7.4.7 Interposed sections Interposed sections are similar to revolved sections with the other drawing detail in the immediate vicinity of the sections removed. An example is shown in Figure 7.15. The outline of an interposed section shall be a Type A line. Further identification is unnecessary. 7.4.8 Removed sections 7.4.8.1 Usual method Removed sections are similar to revolved sections except that the cross-sections are removed from the actual view of the object. The sections are placed on centre-lines extending from the cutting plane. An example is shown in Figure 7.16. The outline of a removed section shall be a Type A line. Further identification is unnecessary. A removed section may be enlarged and the scale indicated. 7.4.8.2 Alternative methods If the method described in Clause 7.4.8.1 is not practicable, the section or sectional views may be removed to some other convenient position on the drawing. Such a section shall be clearly identified and labelled as a section, unless there is no possibility of misinterpretation. The section may be rotated in the same manner as a rotated removed auxiliary view (see Figure 7.17(b)). This also applies to sectional views. NOTES: 1 Figures 7.17(a) and (b) are alternative methods. Only one method should be used. 2 Figure 7.17(a) shows a removed section, translated without rotation. 3 Figure 7.17(b) shows a removed section, translated and rotated. This method should only be used when space is restricted. 7.4.8.3 Disposition of successive sections If, through lack of space, successive sections cannot be arranged in normal projection as illustrated in Figure 7.18(a), the arrangement as removed sections illustrated in Figure 7.18(b) may be used. 7.4.9 Other conventions used in sectioning 7.4.9.1 Fastening elements Where the cutting plane through an assembly contains the centre-line of fastening elements such as bolts, pins, rivets, keys, washers, nuts, screws, or other elements such as shafts, rods, ball and roller bearings, and similar shapes which in themselves do not require sectioning, the elements shall not be sectioned but shall be shown in full outline (see Figure 7.19). COPYRIGHT Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) 89 AS 1100.101—1992 NOTE: For explanation of double-spaced hatching on the right-hand side of section A-A, see Clause 7.4.9.2. FIGURE 7.13 ALIGNED AND AUXILIARY ALIGNED SECTIONAL VIEWS 7.4.9.2 Relatively thin elements Where the cutting plane through an object passes longitudinally through a relatively thin element of the object such as a web, rib, lug or spoke, the outline of the feature may be drawn without hatching in order to avoid a false impression of solidity (see Figure 7.20). Alternatively, the hatching between the outline of the thin element and the main body may be double-spaced, as shown in Figure 7.13. This is recommended where other similar thin sections are involved on the part which is shown in sectional view. Where this method is used, the boundary between the thin and thick sections shall be shown as a hidden outline. Where sections do not cut the rib or spoke, e.g. a wheel with three spokes, the oblique spoke should be drawn as being on the cutting plane. COPYRIGHT Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) AS 1100.101—1992 90 FIGURE 7.15 INTERPOSED SECTIONS COPYRIGHT Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) 91 FIGURE 7.17 PLACEMENT OF SECTIONAL VIEWS COPYRIGHT AS 1100.101—1992 Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) AS 1100.101—1992 92 FIGURE 7.19 SECTION WITH AXIAL FEATURES COPYRIGHT 93 AS 1100.101—1992 FIGURE 7.20 WEB IN LONGITUDINAL SECTION NOT HATCHED Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) 7.4.9.3 Holes In a sectional view of an element, holes may be shown, even if not in the cutting plane. Holes in circular elements should be shown at the true pitch from the centre rather than at the projected distance (see Figure 7.21). FIGURE 7.21 HOLES IN ELEMENTS COPYRIGHT AS 1100.101—1992 94 7.4.9.4 Features located in front of a cutting plane Where it is necessary to represent features located in front of the cutting plane, these features should be indicated with Type G lines (see Figure 3.10). The representation of features located in front of cutting planes is not recommended for drawings of machine parts. 7.4.9.5 Breaks Break lines as illustrated in Figure 7.22 may be used to shorten a view of elongated objects. The lines shall be Type C or Type D. Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) NOTE: Long break lines may be at any convenient angle with outlines or centre-lines of objects or assemblies, provided that clarity or interpretation of the view is not impaired. FIGURE 7.22 USE OF BREAK LINES ON ELONGATED OBJECTS COPYRIGHT 95 AS 1100.101—1992 Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) SECTION 8 DIMENSIONING 8.1 SCOPE This Section sets out recommendations for the dimensioning, including size and geometry tolerancing, of technical drawings. These recommendations relate to drawings which define products in their completely finished state as required by the designer. Such drawings do not necessarily define the manufacturing methods which may be used to comply with the design requirements. Many of the principles and practices, however, can be applied to process drawings which may define products in a partly finished state. The tolerances for form, location, and orientation are indicated on the drawing by using symbolic notation to identify the group, the characteristic to be toleranced, the magnitude of the tolerance, and the applicable datums. Practices unique to architecture, civil, surveying, electrical, and mechanical engineering, as well as welding and surface texture, are included in the appropriate Standards. 8.1.1 Terminology 8.1.1.1 Dimension— (a) a characteristic such as length or angle, of which the magnitude is specified in the appropriate unit of measurement; or (b) the numerical value used on the drawing or specification to define the size of the characteristic in Item (a) (see Figure 8.12). 8.1.1.2 Tolerance—the total amount of variation permitted for the size of a dimension, a positional relationship, or the form of a profile, or other design requirement. 8.1.2 Fundamental rules Dimensioning and tolerancing shall clearly define intent and shall comply with the following: (a) Each necessary dimension of an end product shall be specified. No more dimensions than those necessary for complete definition shall be given. The use of auxiliary dimensions on a drawing shall be minimized. (b) Dimensions shall be selected and arranged to suit the function and mating relationship of a part, and shall not be subject to more than one interpretation. Such dimensions are termed functional dimensions. (c) The drawing should define a part without specifying construction and inspection methods. Thus, only the diameter of a hole is given without indicating whether it is to be drilled, reamed, punched, or made by any other operation. However, in those instances where manufacturing, processing, quality assurance, or environmental information is essential to the definition of requirements, it shall be specified on the drawing or in a document referenced on the drawing. (d) Dimensions should be arranged to provide required information for optimum readability. Dimensions should be shown in true profile views and refer to visible outlines. (e) A 90° angle is implied where centre-lines and lines depicting features are shown on a drawing at right angles and no angle is specified. (f) A 90° basic angle applies where centre-lines of features in a pattern, or surfaces shown at right angles, on the drawing are located or defined by basic dimensions and no angle is specified. (g) Unless otherwise specified, all dimensions are applicable at 20°C. Compensation may be made for measurements made at other temperatures. (h) Each dimension should have a tolerance, except for those dimensions specifically identified as basic, auxiliary, maximum or minimum. The tolerance may be applied directly to the dimension (or indirectly in the case of basic dimensions), indicated by a general note, or located in a supplementary block of the drawing layout. (See Clause 8.3.8.3.) (i) Dimensions for size, form, orientation, and location of features shall be complete to the extent that there is full understanding of the characteristics of each feature. Neither scaling (measuring the size of a feature directly from a technical drawing) nor assumption of a distance or size is permitted. (j) Geometry tolerance shall be specified where essential, i.e. in light of functional requirements, interchangeability, and probable manufacturing circumstances. NOTE: Undimensioned drawings (e.g. loft, printed wiring, templates, master layouts, tooling layout maps) prepared on stable material are excluded, provided that the necessary control dimensions are specified. 8.2 GENERAL DIMENSIONING 8.2.1 Dimensioning symbols Some general symbols used for dimensioning and tolerancing and their application are given in Table 8.1. The shape and size of these symbols are given in Figure 4.14. 8.2.2 Terminology 8.2.2.1 Functional dimension—a dimension which directly affects the functioning of the product. (See Figures 8.1 and 8.2.) COPYRIGHT Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) AS 1100.101—1992 96 FIGURE 8.2 EXAMPLE OF FUNCTIONAL DIMENSIONS FOR KITCHEN CUPBOARD COPYRIGHT 97 AS 1100.101—1992 TABLE 8.1 DEFINITION AND APPLICATION OF DIMENSIONING SYMBOLS Symbol Application Indicates that a dimension refers to the diameter of a circle or cylinder. It shall be placed in front of the dimension. Indicates that a dimension refers to a radius of part of a circle or cylinder. It shall be placed in front of the dimension. Indicates that a dimension refers to the width across flats of a square section. It shall be placed in front of the dimension. Indicates a taper and its direction. The centre-lines shall be parallel with the axis or plane of symmetry of the tapered feature. It shall be placed in front of the slope ratio. Indicates a slope and its direction. The base shall be parallel to the datum plane. It shall be placed in front of the slope ratio. Indicates the centre-line of a part, feature, or group of features. It shall be located adjacent to, or on, the centre-line. Indicates the diameter of spherical surface. It shall be placed in front of the dimension. Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) Indicates the radius of a spherical surface. It shall be placed in front of the dimension. Indicates countersink. It shall be placed in front of the dimension. Indicates counterbore or spotface. It shall be placed in front of the dimension. Indicates depth of a feature. It shall be placed in front of the dimension. Indicates that a dimension refers to the arc length. It shall be placed above the dimension. 8.2.3 Projection and dimension lines and leaders 8.2.3.1 Projection lines Projection lines shall be Type B lines (see Table 3.1) projected from points, lines, or surfaces to enable the dimensions to be placed outside the outline wherever possible. Projection lines shall extend a little beyond the dimension line. Where projection lines are extensions of outlines, they shall start just clear of the outlines. Figure 8.3 illustrates these features and shows recommended dimensions for the extension beyond the dimension line and the clearance mentioned above. Where projection lines refer to points on surfaces or lines, they shall pass through or terminate on the points as shown in Figure 8.4, and, for clarity, oblique projection lines may be used as shown. Where projection lines refer to imaginary points of intersection, they shall pass through or terminate on the points as shown in Figure 8.5, and the points may be emphasized by dots as shown. COPYRIGHT Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) AS 1100.101—1992 98 FIGURE 8.4 PROJECTION LINES FROM POINTS ON SURFACES COPYRIGHT 99 AS 1100.101—1992 Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) FIGURE 8.5 IMAGINARY POINTS OF INTERSECTION EMPHASIZED BY PROMINENT DOTS 8.2.3.2 Dimension lines Dimension lines shall be Type B lines drawn parallel to the direction of measurement and, wherever practicable, shall be placed outside the view of the object, as in Figure 8.3. The space between the first dimension line and part outline should not be less than 3h; the spaces between succeeding dimension lines should not be less than 2h (where h equals the character height). Dimension lines may be interrupted for the insertion of the dimensions when using the aligned method, and they shall be interrupted where necessary when using the unidirectional method (see Clause 8.2.5.1). Arrowheads shall conform to Clause 4.3.3, and shall touch the projection or other limiting line. Where several dimensions are to be given from a common surface, line or point, one of the methods shown in Figure 8.6 shall be used. Where Method (b) or Method (c) is used, a prominent dot shall be placed on the common line. If the surface, line or point is a datum for the dimensions (including basic dimensions) then the dot is replaced by a datum indicator symbol (see Clause 8.3.3.5 and Figure 8.51). The dimension lines and arrowheads in Figure 8.6(b) may be omitted. Where there are several parallel dimension lines given from a common line, the dimensions shall, where practicable, be placed near the arrowhead remote from the common line (see Figure 8.6(a)). A centre-line, or a line which is an extension of a centre-line or of an outline, shall not be used as a dimension line (see Figure 8.7). 8.2.3.3 Leaders A leader is a line used in conjunction with a terminator to indicate where dimension notes, item numbers, or feature identifications are intended to apply (see Figure 8.8). Leaders shall be Type B lines. A leader used to indicate where a dimension applies shall originate at either the beginning or the end of the dimension and terminate in an arrowhead (see Figures 8.7 and 8.19(a)). A leader indicating a dimension may terminate on the dimension line without an arrowhead (see Figure 8.8(b)). A leader from a note may terminate in an arrowhead (see Figure 8.8(a)) or in a dot (see Figure 8.8(c)), whichever is appropriate. Arrowheads shall always terminate on a line and dots shall be within the outlines of the object. Arrowheads shall conform to Clause 4.3.4. Leaders shall not be visually parallel to adjacent dimension lines or projection lines, and shall be nearly normal and not more than 45° from the normal to the lines to which they refer (see Figure 8.9). Long leaders should be avoided even if it means dimensioning identical features as in Figure 8.10(a) or using letter symbols adjacent to the features as shown in Figure 8.11(a). Dimensional information may be shown by leaders as in the left-hand figure of Figure 8.11. 8.2.4 Dimensions 8.2.4.1 Numerical values The decimal sign should be a dot in accordance with Clause 4.1.6.1. Dimensions should be expressed to the full number of decimal places necessary for complete definition of the design requirements. Where the quantity is less than one, the decimal sign shall be preceded by zero, e.g. 0.25 A full space shall divide each group of three numerals to the right or to the left of the decimal sign, e.g. 125 000 2 500 2.498 5 2.498 55 NOTE: For further information of presentation of numerical values, see AS 1000. Where a dimension is an integral number of units, both the decimal sign and the zeros following the decimal sign shall be omitted, e.g. 50 not 50.0 Numerical values shall be clearly indicated adjacent to a dimension line or a leader or in a note. COPYRIGHT Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) AS 1100.101—1992 100 FIGURE 8.7 CENTRE-LINES AND EXTENSION LINES NOT TO BE USED AS DIMENSION LINES COPYRIGHT Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) 101 FIGURE 8.9 LEADERS TOUCHING LINES COPYRIGHT AS 1100.101—1992 Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) AS 1100.101—1992 102 8.2.4.2 Linear dimensions Linear dimensions consist of two elements, the numerical value and the unit of measurement. The preferred unit for linear dimensions on drawings shall be the millimetre. Units shall be clearly indicated by one of the following methods: (a) Where only one unit is used — by the display of a prominent note, e.g. DIMENSIONS IN MILLIMETRES (b) Where two or more units are used, but one unit occurs more frequently than the other unit(s) — (i) most frequently used unit — by a prominent note, e.g. UNLESS OTHERWISE STATED DIMENSIONS IN MILLIMETRES (ii) other unit(s) — by placing the appropriate unit symbol after the numerical value, separated by a single space, e.g. 14 m (c) Where neither (a) nor (b) applies — by placing the appropriate unit symbol after the numerical value, separated by a single space. 8.2.4.3 Angular dimensions Angular dimensions shall be expressed either in degrees and decimal parts thereof, in degrees and minutes, or in degrees, minutes and seconds, e.g. 22.5° 22°30’ 2°30’30” 2°4’5 Where an angle is less than one degree it shall be expressed as follows — 0.5° 0°30’ 0°30’30” 0°0’30” Angles of 90° need not be dimensioned unless required for clarity. Leading zeros may be used before minutes and seconds when these figures are less than 10, e.g. 2°04’05” COPYRIGHT 103 AS 1100.101—1992 8.2.5 Arrangement of dimensions 8.2.5.1 General General criteria for the arrangement of dimensions are as follows: (a) Dimensions shall be placed on drawings using either the unidirectional method (see Figure 8.12(a) and (c)) or the aligned method (see Figure 8.12(b) and (c)). In the unidirectional method, dimensions are inscribed parallel to the bottom edge of the drawing, with vertical or inclined dimension lines being interrupted for insertion of dimensions, if space permits. In the aligned method, each dimension is inscribed parallel to its dimension line so as to be read from the bottom edge or from the right side of the drawing avoiding the hatched area shown. Dimensions and notes shown with leaders shall be inscribed by the unidirectional method (see Figure 8.12(a)). NOTE: Drawings and sketches for use in publications such as handbooks should be dimensioned by the unidirectional method. Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) (b) Where there are several parallel dimension lines, the dimensions should be staggered for clarity as in Figure 8.13. (c) Overall dimensions shall be placed outside the intermediate dimensions as in Figure 8.14. (d) Various methods of dimensioning narrow spaces are shown in Figure 8.12. (e) The free or floating end of a dimension line defining a feature not completely shown on a drawing shall be terminated by a double arrowhead (see example in Figure 8.22). 8.2.5.2 Tabular presentation of dimensions Where there are a number of features on a single drawing defined by coordinates from X and Y datums, the dimensions of each feature may be given in tabular form (see Figure 8.15). Where one drawing is used to specify the dimensional requirements of a number of parts with similar configurations, the dimensions may be given in tabular form (see Figure 8.16). FIGURE 8.12 PLACING OF DIMENSIONS IN RELATION TO DIMENSION LINES COPYRIGHT Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) AS 1100.101—1992 104 FIGURE 8.14 OVERALL DIMENSIONS PLACED OUTSIDE INTERMEDIATE DIMENSIONS 8.2.5.3 Not-to-scale dimensions Where it is necessary or desirable to indicate that a particular dimension is not to scale, the dimension shall be underlined with a full thick line, i.e. Type A (see dimension ∅ 49 in Figure 8.14). Dimensions over breaks, dimensions locating inconveniently placed centres and associated radii, and dimensions which from the context of the drawing or by method of inscription may not be to scale shall not be underlined. 8.2.5.4 Terminology — Auxiliary dimension An auxiliary dimension is a dimension given solely for information or reference, but which is not necessary for function or assembly. 8.2.5.5 Auxiliary dimensions — General Where the overall dimension is shown, one of the intermediate dimensions is redundant, and shall not be dimensioned (see Figure 8.14). Exceptions may be made where such dimensions would provide useful information, in which case they should be given as ‘auxiliary’ dimensions. Where all the intermediate dimensions are shown, the overall dimension should generally be given as an auxiliary dimension. (See Figure 8.17.) Auxiliary dimensions shall be enclosed in parentheses, and shall not be toleranced (see Figures 8.17 and 8.18). Auxiliary dimensions relating to position shall be based on the dimensions which define the true theoretical positions of the features concerned. Where they relate to size, they shall normally be based on the mean sizes of the features concerned. In other cases, the basis of calculation shall be clearly stated on the drawing. Auxiliary dimensions shall not govern acceptance or rejection of the product. An auxiliary dimension is sometimes called a reference dimension. COPYRIGHT Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) 105 AS 1100.101—1992 FIGURE 8.15 TABULAR PRESENTATION OF DIMENSIONS OF A COMPONENT 8.2.6 Methods of dimensioning common features Many of the methods of dimensioning features described in this Clause are equally applicable to dimensioning of features other than those shown. 8.2.6.1 Diameters Criteria for presentation of diameters are as follows: (a) Symbol A dimension indicating the diameter of a circle, cylinder, or spherical surface shall be preceded by the symbol ∅, separated by a space (see Figure 8.19). (b) Arrangement Dimensions of diameter shall be placed on the most appropriate view to ensure clarity, as for instance on a longitudinal view in preference to an end view consisting of a number of concentric circles (see Figure 8.20). (c) Method of dimensioning Circles representing circular features in end view shall be dimensioned by one of the methods shown in Figure 8.19. The diameter of circular features in longitudinal view shall be dimensioned by one of the methods shown in Figures 8.20, 8.21, and 8.23. (d) Restricted space Where space is restricted, one of the methods shown in Figure 8.22 may be used. (e) Spherical surfaces The diameter of a spherical surface shall be dimensioned using the symbol S∅ (see Figure 8.23). COPYRIGHT AS 1100.101—1992 106 PART NO 1 2 3 4 5 6 millimetres A B C D E 10 10 10 10 12 12 20 20 20 20 25 25 30 35 30 35 40 50 15 15 12 12 20 20 42 47 40 45 55 65 Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) FIGURE 8.16 TABULAR PRESENTATION OF DIMENSIONS OF SIMILAR COMPONENTS FIGURE 8.17 OVERALL LENGTH ADDED AS AN AUXILIARY DIMENSION COPYRIGHT Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) 107 AS 1100.101—1992 FIGURE 8.19 PLACEMENT OF DIAMETER DIMENSIONS IN END VIEW 8.2.6.2 Radii Criteria for the presentation of radii are as follows: (a) Symbol A dimension indicating the radius of part of a circle, cylinder or spherical surface shall be preceded by the symbol R, separated by a small space. (b) Arrangement Radii shall be dimensioned by a dimension line which passes through, or is in line with, the centre of the arc. The dimension line shall have one arrowhead only, that touching the arc. Radii of arcs which need not have their centres located shall be dimensioned by one of the methods shown in Figure 8.24. (c) Locating inconveniently placed centres Where the centre of an arc cannot conveniently be shown in its correct position, and yet needs to be located, one of the methods shown in Figure 8.25 shall be used. The portion of the dimension line which touches the arc shall be normal to the arc. (d) Radius of a spherical surface The radius of a spherical surface shall be dimensioned using the symbol SR. Examples are shown in Figure 8.26. COPYRIGHT Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) AS 1100.101—1992 108 COPYRIGHT Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) 109 COPYRIGHT AS 1100.101—1992 Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) AS 1100.101—1992 110 COPYRIGHT 111 AS 1100.101—1992 8.2.6.3 Squares A dimension indicating the size of a square should be preceded by the symbol by a single space, as shown in Figure 8.27. , separated FIGURE 8.27 SQUARE SECTION 8.2.6.4 Holes Criteria for the presentation of holes are as follows: (a) Form or shape Form or shape should be defined by an appropriate symbol, e.g. ∅ or . NOTE: The word ‘hole’ or ‘holes’ may be used for clarity. Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) (b) Sizes The depth of a hole refers to the depth of the full form hole. Holes with unspecified depths shall be construed as through holes (see Figure 8.28). The depth of a hole may be preceded by the depth symbol . FIGURE 8.28 HOLES (c) Location The location of holes may be defined by specifying the diameter of pitch circles as shown in Figure 8.29 or by specifying the rectangular coordinates or centre distances as shown in Figure 8.30. Holes which are drawn with a common axis as shown in Figure 8.28(d) imply a requirement of concentricity (see Clause 8.10.4). Holes which are drawn with a common centre-line as shown in Figure 8.30(a) imply a requirement of symmetry (see Clause 8.10.5). COPYRIGHT AS 1100.101—1992 112 Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) FIGURE 8.29 POSITIONING OF HOLES BY ANGULAR DIMENSIONING ON A PITCH CIRCLE 8.2.6.5 Equal dimensions When a dimension is divided into several parts the preferred method is shown in Figure 8.31(a). The word ‘equal’ or symbol ‘=’ shall not be used to indicate those dimensions which are nominally equal (see Figure 8.31(b)). 8.2.6.6 Positioning of curved surfaces Circumferential dimensioning of the spacing of features on a curved surface shall be indicated by a curved dimension line as shown in Figure 8.32 with the arc symbol above the dimension. The curved dimension line shall be drawn relative to the curved surface as in Figure 8.32(a). It may be desirable in certain cases to indicate the surface on which the dimension is to be taken by dots as shown in Figure 8.32. Chordal dimensioning of the spacing of features on a curved surface shall be indicated as shown in Figure 8.32(c). 8.2.6.7 Chamfers Chamfers shall be dimensioned by one of the methods shown in Figure 8.33. However, chamfers of 45° should be dimensioned by one of the methods shown in Figure 8.33(b). Small 45° chamfers may be dimensioned as shown in Figure 8.33(c). 8.2.6.8 Countersinks, counterbores, spotfaces and depth Countersinks, counterbores, spotfaces, and depth shall be dimensioned in accordance with the examples given in Figure 8.34. 8.2.6.9 Screw threads Criteria for the presentation of screw threads are as follows: (a) Designation Screw threads shall be specified by using the designation shown in the appropriate Standard, e.g. M6 x 1-6g When specifying special screw threads, the limits of which need to be shown, the dimensions for the major, pitch, and minor diameters shall be given as in Figure 8.35. (b) Undercuts Undercuts, where required, should be dimensioned on the drawing in accordance with AS B199. (c) Length of thread The length of full thread or the distance to the end of full thread shall be specified using one of the methods shown in Figures 8.36 to 8.39. Where it is necessary to limit the length of full threads and runouts, the method shown in Figures 8.38 and 8.39(c) shall be used. NOTES: 1 The end of a full thread is the point at which the thread profile ceases to be fully formed. 2 Methods of indicating incomplete threads are shown in Figures 8.36, 8.37, 8.38, and 8.39(c) and (d). Two methods are shown, Type B lines at 30° to the axis in all but Figures 8.39(c) in which the extent of the incomplete threads is shown by a note. (d) Threaded holes Threaded holes shall be dimensioned by one of the methods shown in Figure 8.39. Holes with unspecified depths shall be construed as threaded right through. (See Figure 8.39(b).) COPYRIGHT Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) 113 FIGURE 8.30 POSITIONING OF HOLES BY COORDINATES COPYRIGHT AS 1100.101—1992 Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) AS 1100.101—1992 114 FIGURE 8.32 CURVED SURFACES COPYRIGHT 115 AS 1100.101—1992 Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) FIGURE 8.33 CHAMFERS 8.2.6.10 Tapers Tapers should be dimensioned by either of the following methods: (a) By indicating the design taper or angle and one diameter or width positioned relative to some datum surface (see Figure 8.40(a)). (b) By specifying two diameters or widths positioned relative to a single datum surface (see Figure 8.40(b)). The taper shall be expressed as a ratio, e.g. 0.2:1 1:10 3:100 NOTES: 1 Taper is the change in diameter or width per unit axial length. 2 There is also a further method of dimensioning tapers known as the three-toleranced dimension method, which is not recommended. For further information, see Clause 8.3.13.5. 8.2.6.11 Profiles and curved surfaces A curved line composed of circular arcs should be dimensioned by radii as in Figure 8.41. Coordinates, as in Figure 8.42, should be used only if the preferred method is impracticable. Where the coordinate method is used, the coordinates shall be close enough to ensure that the design requirement is satisfied. The coordinates may be rectangular or polar, and, where convenient, may be given in tabular form. When dimensioning cam profiles, it is often convenient to give the dimensions in association with a replica of the follower (see Figure 8.43). 8.2.6.12 Taper and slope symbols Symbols used for specifying taper and slope for conical and flat tapers are shown in Figures 8.16 and 8.44. These symbols are always shown to conform to the ISO method. 8.2.7 Notes on drawings Notes may be classified as general or local as follows: (a) General notes General notes may be used with advantage to specify requirements which would otherwise need to be repeated many times on a particular drawing. It is recommended that such notes be grouped together. A typical example is— CASTING RADII ARE 5 mm UNLESS OTHERWISE STATED (b) Local notes Local notes refer to local requirements and should be placed near the point to which they refer. Figure 8.8 shows a typical example of a local note. COPYRIGHT Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) AS 1100.101—1992 116 FIGURE 8.34 COUNTERSINKS, COUNTERBORES, SPOTFACES AND DEPTH COPYRIGHT Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) 117 COPYRIGHT AS 1100.101—1992 Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) AS 1100.101—1992 118 FIGURE 8.39 DIMENSIONING OF THREADED HOLES COPYRIGHT Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) 119 AS 1100.101—1992 8.3 GENERAL TOLERANCES AND RELATED PRINCIPLES 8.3.1 General This Clause establishes terminology and practices for expressing tolerances on linear and angular dimensions, material condition modifiers and their application, and interpretations governing limits and tolerances. 8.3.2 Terminology 8.3.2.1 Axis (of a feature) — the locus of the median points of all cross-sections of the considered feature. 8.3.2.2 Basic dimension A theoretically exact dimension defining a positional or angular relationship between two or more features, or the form of a surface or profile. This dimension is shown in a box. (See Figure 8.45.) COPYRIGHT Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) AS 1100.101—1992 120 8.3.2.3 Datum—a perfect geometric element, such as a point or a line or a plane which alone or in combination with others of its kind defines precisely the basic shape of the geometric reference frame for a particular group of features. See Figures 8.46 and 8.47. Appendix H provides further information on datums. NOTE: The plural in this context is ‘datums’ not ‘data’. 8.3.2.4 Datum dimension—a basic dimension establishing true position of a datum or a datum target. (See Figure 8.48.) COPYRIGHT Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) 121 COPYRIGHT AS 1100.101—1992 FIGURE 8.46 DATUM, DATUM FEATURE, AND SIMULATED DATUM—EXAMPLE 1 Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) AS 1100.101—1992 122 FIGURE 8.48 DATUM DIMENSION (SHOWN IN BOX) 8.3.2.5 Datum feature—a real feature of an item (such as a surface, a hole) which is used to establish the location of a datum. (See Figures 8.46 and 8.47.) NOTE: Datum features are subject to manufacturing errors and variations and should be assigned tolerances appropriate to their design functions. 8.3.2.6 Datum, simulated—a feature or features of equipment such as a surface plate, Australian height datum, construction datum or survey bench mark or from which the corresponding datum point, line or plane is derived. (See Figures 8.46 and 8.47.) 8.3.2.7 Datum target—a specific point, line or area on the item used to establish a datum. 8.3.2.8 Feature—an individual characteristic such as a flat surface, a cylindrical surface, two parallel surfaces, shoulder, screw thread, slot, profile, window, culvert, building, property boundary, road, river or railway. 8.3.2.9 Group (of features)—two or more features which are functionally related. 8.3.2.10 Size—term denoting magnitude of any kind. 8.3.2.11 Size, actual—the size determined from a number of local sizes of a dimension of an individual feature. 8.3.2.12 Size, least material— (a) For an external feature—the minimum limit of size specified on the drawing. (b) For an internal feature—the maximum limit of size specified on the drawing. COPYRIGHT 123 AS 1100.101—1992 8.3.2.13 Size, limits of—the maximum and minimum sizes permitted for a dimension (see Figure 8.50, Method A). NOTE: The difference between the limits of size is equal to the tolerance. 8.3.2.14 Size, local—any individual measurement of the dimension of a feature. (See Figure 8.49.) Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) FIGURE 8.49 LOCAL SIZE 8.3.2.15 Size, mating (a) For an external feature—the dimension of the smallest similar perfect feature which can be circumscribed about the feature so that it just contacts the surface at the highest points. (b) For an internal feature—the dimension of the largest similar perfect feature which can be inscribed within the feature so that it just contacts the surface at the highest points. NOTE: Mating size only refers to spherical, cylindrical, and plane parallel features. See Figure 8.85. 8.3.2.16 Size, maximum material— (a) For an external feature—the maximum limit of size specified on the drawing (see Figure 8.85). (b) For an internal feature—the minimum limit of size specified on the drawing. 8.3.2.17 Size, nominal—the size by which an item is designated as a matter of convenience. Examples: M20 screw thread; 75 mm × 50 mm timber wall plates. 8.3.2.18 Tolerance—see Clause 8.1.1.2. 8.3.2.19 Tolerance, bilateral—a tolerance in which variation is permitted only in both directions from the specified dimension. (See Figure 8.53, Method C.) 8.3.2.20 Tolerance, unilateral—a tolerance in which variation is permitted only in one direction from the specified dimension. (See Figure 8.53, Method B.) 8.3.2.21 Tolerance zone—a zone within which the surface or median plane of axis of a feature is to be contained. 8.3.3 Application of tolerancing symbols 8.3.3.1 General This Clause establishes the symbols for specifying geometric characteristics and other dimensional requirements on engineering drawings. 8.3.3.2 Symbol construction Information related to the construction, form, and proportion of individual symbols described herein is contained in Clause 4.3. 8.3.3.3 Feature symbols The use of feature symbols is as follows: (a) Feature identification The feature identification symbol consisting of the rectangular frame symbol containing the feature identification letter is used to identify a feature as shown in Figure 8.50(a). (b) Datum feature identification Consists of the datum feature symbol located on the datum feature and joined to a feature identification symbol containing the datum identification letter (see Figure 8.50(b)). NOTE: The datum identification symbol may be unfilled. COPYRIGHT AS 1100.101—1992 124 Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) 8.3.3.4 Datum identifying letters Letters of the alphabet (except I, O, E, P, R, S, M, and Q) are used as datum identifying letters. Each datum feature requiring identification shall be assigned a different letter. Where datum features requiring identification on a drawing are so numerous as to exhaust the single alpha series, the double alpha series shall be used — AA through AZ, BA through BZ, etc. It is recognized that feature letters should not be duplicated for other purposes on the drawing. 8.3.3.5 Datum target symbol The datum target symbol is a circle divided horizontally into two halves (see Figure 8.51). The lower half contains a letter identifying the associated datum, followed by the target number assigned sequentially starting with 1 for each datum. Where the datum target is an area, the area size may be entered in the upper half of the symbol; otherwise, the upper half is left blank. A radial line attached to the symbol is directed to a target point (indicated by an ‘X’), target line, or target area, as applicable (see Figures 8.115, 8.116, and 8.117). 8.3.3.6 Basic dimension symbol The feature identification symbol is used to identify a basic dimension as shown in Figure 8.45. 8.3.3.7 Maximum material condition symbol The symbol is used to indicate ‘at maximum material condition’ as shown in Figure 8.84. The use of this symbol in local and general notes is prohibited. 8.3.3.8 Projected tolerance zone symbol The symbol is used to indicate a projected tolerance zone as shown in Figure 8.94. The use of this symbol in local and general notes is prohibited. 8.3.3.9 Dimension datum symbol The datum identification symbol is used to indicate the origin of a dimension between two features (see Figure 8.52). 8.3.3.10 Envelope symbol The symbol is used to indicate the application of the envelope principle as shown in Figure 8.58. The use of this symbol in local and general notes is prohibited. FIGURE 8.52 DIMENSION DATUM SYMBOL COPYRIGHT 125 AS 1100.101—1992 8.3.4 Principle of independency This fundamental tolerancing principle states that each requirement specified on a drawing, such as a dimensional tolerance or a geometrical tolerance, shall be met independently without reference to any other dimension, tolerance, or characteristic unless a particular relationship is specified by a separate indication. Following the ‘principle of independency’— (a) a toleranced size on a feature controls the size of the feature but not its form; and (b) a toleranced size between features controls the position between the features but not the form of either feature. 8.3.5 Envelope principle When applied to a feature this principle requires that if that feature is finished everywhere at its maximum material limit of size, it must be perfect in form over a specified length of that feature, where appropriate. It is indicated by the symbol following the dimension, as shown in Figure 8.58. 8.3.6 Maximum material principle The maximum material principle is a tolerancing principle which takes into account, where indicated in appropriate cases, the mutual dependence of tolerances of size, location, and orientation, and permits additional tolerance as the considered feature of a particular part departs from its maximum material condition. It shall be specified on the drawing by the symbol following the dimension as shown in Figure 8.86(A). 8.3.7 Tolerance indication methods Tolerances may be expressed as follows: (a) By specific limits of size or by limits of tolerance applied directly to the dimension. (b) By referencing the appropriate national or other Standards or specifications. (c) Indirectly by association with a geometry tolerance. (d) In a general tolerance note referring to those dimensions and geometry requirements on a drawing for which tolerances are not otherwise specified. Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) NOTE: Tolerances are not applicable to basic dimensions shown in a rectangular frame on the drawings. 8.3.8 Direct tolerancing methods 8.3.8.1 Linear dimensions of features The tolerance of a linear dimension of a feature shall be expressed by one of the methods shown in Figure 8.53. There is no difference in the interpretation of these methods of expression, each of which does no more than define the maximum and minimum limits of size. When using Method A (see Figure 8.53), the larger limit of size shall be placed above the lower limit of size, and both dimensions shall be given to the same number of decimal places. When using Method B and one of the limits of tolerance is zero, this limit shall be expressed by the figure ‘0’ and shall not be preceded by + or −. When using Method B or Method C, the dimensions shall be expressed as in Clause 8.2.4.1. NOTE: The following method is sometimes found convenient in design offices but is not recommended for use on drawings issued for purposes of manufacture: For shafts: 40 e7 or 40 e7 (-0.05 ) (-0.075) For holes: 40 H8 or 40 H8 (-0.039) (0 ) The relevant symbols and limits are taken from AS 1654. Where it is necessary to specify only one limit of size of a dimension (e.g. the minimum length of full thread or the maximum radius that is permitted in a corner), the abbreviation ‘MAX’ or ‘MIN’ shall be used, e.g. 20 MIN LENGTH FULL THREAD R 0.5 MAX 8.3.8.2 Angular dimensions The tolerances for angular dimensions limit the general direction of lines and surfaces. Such tolerances do not limit form deviations of the features forming the angles. The angle between two surfaces shall be defined as the angle between planes representing each surface. The direction of each plane is defined as the direction of the two parallel planes enclosing a surface, these two parallel planes being the minimum distance apart. A similar definition applies to the angle between two lines. (See also Appendix F.) Tolerancing of angular dimensions shall be expressed in a similar way to tolerancing of linear dimensions (see Figure 8.54). NOTE: Unless otherwise specified, where a general tolerance note on the drawing includes angular tolerances, it applies to features shown at specified angles and at implied angles, e.g. 90°. COPYRIGHT AS 1100.101—1992 126 Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) FIGURE 8.53 TOLERANCING OF LINEAR DIMENSIONS 8.3.8.3 General tolerance notes Examples of tolerancing by general notes or reference to national and other Standards are shown in Figure 8.55. NOTE: For guidance on general tolerances of machined components, see AS 1100.201. 8.3.9 Interpretation of limits of dimensions 8.3.9.1 Dimensional limits For the purpose of determining conformance within limits, the measured value is compared directly with the specified value and any deviation outside the specified limiting value signifies non-conformance with the limits. Regardless of the number of decimal places, dimensional limits are to be interpreted as if they were continued with zeros. Examples: 12.2 12.0 12.01 12.00 means means 2.20 12.00 12.010 12.000 . . . . . . . . .0 .0 .0 .0 8.3.9.2 Plated or coated parts Where a part is to be plated or coated, the drawing or referenced document shall specify whether the dimensions are before or after plating. Typical examples of notes are as follows: (a) DIMENSIONAL LIMITS APPLY AFTER PLATING. (b) DIMENSIONAL LIMITS APPLY BEFORE PLATING. (For coatings other than plating, substitute the appropriate term.) 8.3.9.3 Interpretation of toleranced linear dimensions The interpretations of the toleranced linear dimensions on the thin rectangular plate shown in Figure 8.56(a) are as follows: (a) Length and width dimensions of the plate Following the interpretation of size dimensions (see Clause 8.3.3) and using a two point method of measurement, the distance between the vertical sides of the plate is to be in the range 495 to 505. The tolerance for this dimension is obtained from the general tolerance note, i.e. 500 − 5 = 495 and 500 + 5 = 505. The distance between the horizontal sides of the plate is determined likewise and it is to be in the range 249 to 250. These dimensions are illustrated in Figure 8.56(b). Note that these two dimensions imply no control of form (flatness) or orientation (squareness, parallelism) of the sides of the plate. However, the general angle tolerance note requires the angles between the sides of the plate to be within the range 89° to 91°. An example of the angle tolerance applied to two of the four sides of the plate are shown in Figure 8.56(b). COPYRIGHT Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) 127 Tolerance except where otherwise stated: Linear Angular Flatness and straightness Runout ±0.2 ±1° ±0.2 0.2 AS 1100.101—1992 Tolerances on dimensions (except where otherwise stated): Up to 6 Over 6 up to 30 Over 30 up to 120 Over 120 up to 315 All angles (a) All screw threads to AS 1275 ±0.1 ±0.2 ±0.3 ±0.5 ±1° (b) Tolerance on casting thickness ±1% (c) (d) FIGURE 8.55 EXAMPLES OF GENERAL TOLERANCE NOTES COPYRIGHT Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) AS 1100.101—1992 128 (b) Size and position of the hole in the plate Following the interpretation of size dimensions (see Clause 8.3.3), the diameter of the hole is to be in the range 50 to 51 at all two point measurements around the hole as shown in Figure 8.56(c). There is no form specification on the shape of the hole, e.g. circularity, cylindricity. The centre of the hole is given by the axis of the largest cylinder that will fit into the actual hole (see Paragraph (c)). The position of the hole is the shortest distance between the left vertical side and lower horizontal side of the plate and the axis of this cylinder. These dimensions are to be in the ranges 99 to 101 and 120 to 130 as shown in Figure 8.56(d). Note that each of the above dimensions apply independently of all the other dimensions on the drawing. (c) Positioning the axis of a datum and non-datum cylindrical feature The axis of a cylindrical feature is the axis of the largest inscribed cylinder of a hole or the smallest circumscribed cylinder of a shaft. It is located so that any possible movement of the cylinder in any direction is equalized. This is illustrated in Figure 8.57 for a hole. The interpretation applies to both datum and non-datum cylindrical features. 8.3.10 Envelope principle (see Clause 8.3.5) With the envelope condition the maximum material limit of size (i.e. the high limit of size of an external feature or the low limits of size of an internal feature) defines a limit of perfect form for the relevant surfaces. In other words, if a feature is everywhere on its maximum material limits of size, it must be perfect in form. If the feature is not on its maximum material size, errors of form are permitted, provided that no part of the finished surface crosses the maximum material limit of form and the feature is in accordance with its specified limits of size. This principle corresponds to the ideal control exercised by correctly designed full form gauges. In the interest of using standardized gauge blanks, it shall be assumed that, unless otherwise stated, the length over which the above interpretation applies (L) is given by the following equation: L = 33.2(1.145 − e−0.04D ) where D is the maximum material size of the feature. For information on gauge blank sizes, see AS B129. Figure 8.58 shows typical extreme errors of form which could be permitted without contravening the above principle. 8.3.11 Tolerances between features 8.3.11.1 General Tolerances on dimensions that position features may be applied to those dimensions by the position tolerancing method described in Section 8.10, or directly as follows. 8.3.11.2 Dimensional limits related to a datum In certain cases it is necessary to indicate that a dimension between two features shall originate from one of these features and not the other. Such a case is illustrated in Figure 8.59, where a part having two parallel surfaces of unequal length is to be mounted on the shorter surface. In this example, the datum identification symbol described in Clause 8.3.3.10 signifies that the dimension originates from the shorter surface and dimensional limits apply to the other surface. Without such indication either surface can be selected as the datum. 8.3.11.3 Interpretation of toleranced centre distances Limits of centre distances may be expressed by one of the methods shown in Clause 8.3.8.1. The interpretation of toleranced centre distances in Figure 8.60(a) is shown in Figure 8.60(b). Each of the three position requirements indicated in Figure 8.60(b) shall be satisfied independently. For example, the axis of the left-hand hole must lie within the tolerance zone shown in Figure 8.60(b)(i) and independently within that shown in Figure 8.60(b)(ii). Except where otherwise indicated, the limits of centre distances shall be observed regardless of the actual finished sizes of the features concerned. Refer to Appendix H for location of axis of holes. 8.3.11.4 Application In cases where toleranced centre distances are used and the functional requirement is for— (a) control of pitch of adjacent holes, then chain dimensions as shown in Figure 8.61(a) shall be used; or (b) control of position of each hole relative to a datum surface, then progressive dimensions as shown in Figure 8.61(b) shall be used. Toleranced centre distances are suitable for defining the distance between two features, e.g. for the position of a hole relative to a flat surface or the distance between a pair of holes, particularly where the magnitude of the tolerance is different in two directions. Typical applications of toleranced centre distances are shown in Figure 8.62. NOTES: 1 It should be noted that toleranced centre distances are normally checked individually, i.e. from feature to feature. Therefore, where there are more than two features which need to be related together in a group, the use of position tolerances should be considered because they avoid accumulation of tolerances and enable the requirements to be specified more precisely. (See Appendix G.) 2 Where only arrowheads are used, as in Figure 8.61, there is no preferred datum for the dimension and it should be measured point to point. COPYRIGHT Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) 129 FIGURE 8.56 INTERPRETATION OF LINEAR DIMENSIONS COPYRIGHT AS 1100.101—1992 AS 1100.101—1992 130 Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) FIGURE 8.57 POSITIONING THE AXIS OF A CYLINDRICAL FEATURE 8.3.12 Angular surfaces—Tolerancing and interpretation 8.3.12.1 General An angular surface may be located by a combination of linear dimensions and an angle or by linear dimensions alone. Each arrangement of dimensions and tolerances has the effect of specifying a particular tolerance zone within which the surface must lie. The shape and extent of the zone thus specified depends on the dimensioning method chosen, and on the way tolerances are arranged around the locating dimensions. 8.3.12.2 Cumulative angular tolerancing If an angular surface is located by a combination of linear and angular dimensions, both of which are toleranced as in Figure 8.63(a), each dimensional requirement shall be satisfied separately. In this example — (a) any point on the top surface must lie between 9.8 mm and 10.0 mm above the horizontal datum face as in Figure 8.63(b)(i); (b) the angular surface must intersect the horizontal datum face along a line, the points of which are between 27.8 mm and 28.0 mm from the right-hand datum face, as in Figure 8.63(b)(ii); and (c) the angle (dihedral angle) between the angular surface and the horizontal face must lie between 109°30’ and 110° as in Figure 8.63(b)(iii). 8.3.12.3 Basic angular tolerancing The basic angle tolerance method is illustrated in Figures 8.64(a) and 8.65. No specific tolerance is placed on the angle which is indicated as basic. This means that the actual variation permitted to the angle is defined by the tolerance on the 0 associated linear dimension, viz.28-0.2 (in Figure 8.64(a)). This toleranced dimension together with the angle define a tolerance zone within parallel boundaries as shown in Figure 8.63(b) and no part of the actual surface shall exceed these boundaries. 8.3.13 Tapers NOTE: This Clause applies not only to cones but also to all tapered features. 8.3.13.1 Methods of specifying tapers The following methods of specifying the required accuracy of tapered features are recommended: (a) Basic taper (or basic angle) method — where the accuracy of taper is controlled solely by a tolerance of size and where perfect form is required at MMC. NOTE: The envelope principle is embodied in a basic taper specification. Hence the symbol is not required. (b) Toleranced taper (or angle) method — where the angle or taper is directly toleranced independently of the tolerance of size. (c) Fitting to gauge or mating part. There is also one further method known as the ‘three toleranced dimensions method’. This is detailed in Clause 8.3.13.5. COPYRIGHT Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) 131 AS 1100.101—1992 FIGURE 8.58 (in part) EXAMPLES OF EXTREME ERRORS OF FORM ALLOWED BY DIMENSIONAL LIMITS COPYRIGHT Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) AS 1100.101—1992 132 FIGURE 8.58 (in part) EXAMPLES OF EXTREME ERRORS OF FORM ALLOWED BY DIMENSIONAL LIMITS COPYRIGHT 133 AS 1100.101—1992 Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) FIGURE 8.59 RELATING DIMENSIONAL LIMITS TO A DATUM 8.3.13.2 Basic taper (or basic angle) method The term ‘basic taper’ (or ‘basic angle’) means that the tolerance specified for the size of the feature applies at all cross-sectional planes throughout its length and so limits errors of size. Basic angle (or basic taper) is indicated as shown in Figure 8.65(a). Figure 8.65(a) shows a tapered feature dimensioned by a basic angle and with its size specified by a toleranced dimension at one end. The tolerance diagram in Figure 8.65(b) illustrates how the tolerance of 0.05 applies at all cross-sectional planes throughout the length of the tapered feature. Figure 8.66(a) shows a tapered feature dimensioned by a basic taper and with its size specified by a toleranced dimension at a plane located by a datum dimension. The tolerance diagram in Figure 8.66(b) illustrates how the tolerance of 0.05 applies to all cross-sectional planes throughout the length of the tapered feature. Figure 8.67(a) illustrates the use of a basic taper in conjunction with a datum dimension which defines a cross-sectional plane which must be located within specified limits in relation to the left end of the piece. Figure 8.67(b) gives the tolerance diagram that results from the application of the 0.01 tolerance to the location of all cross-sectional planes throughout the length of the tapered feature. The tolerance diagrams Figure 8.66(b) and Figure 8.67(b) show that the nature of the control of size, form and location is the same whenever a basic taper (or angle) is specified. Where the method of dimensioning shown in Figure 8.66(a) or Figure 8.67(a) is used, either the diameter or the distance must be a datum dimension. If both were directly toleranced, the tolerances would be cumulative in their effect on the location of the tapered surface in relation to the end of the datum face. NOTE: For simplicity, the interpretation in all figures shows the least material envelope symmetrically disposed with respect to the maximum material envelope. In practice, this will not be far from the truth, although there is, in fact, no least material limit of perfect form. Any error of form may be present within the maximum material envelope, provided that the taper is everywhere within its least material limits of size at all sections (see Figure 8.68). 8.3.13.3 Toleranced taper (or angle) method In the tolerance taper method, a tolerance is applied directly to the taper (or the included angle) independently of the tolerance which is specified for the size of the feature (see Figures 8.69 and 8.71). Therefore, the tolerance of size applies only at the plane at which the dimension is shown on the drawing and NOT at every cross-sectional plane as is the case with the basic taper method. This method is used where the allowable variation of taper (or angle) is very much more restrictive than the allowable variation in size. The tolerance on taper shall be applied to the numerator of the ratio. In this method, the tolerancing of size shall be expressed as either a tolerance on diameter (or width) at a datum reference plane, which may be within or external to the component (see Figure 8.69(a)), or as a datum diameter (or width) at a toleranced distance from some reference plane (see Figure 8.70(a)). The criteria for acceptance is that each dimensional requirement is satisfied independently, i.e. when using a toleranced diameter as shown in Figure 8.69(a), the diameter, ∅ X (or width) at the specified reference plane shall be within the limits of size as shown in Figure 8.69(b)(ii) and the angle between the generator and the axis shall be within the limits of size as shown in Figure 8.69(b)(i). Using a toleranced length, instead of a toleranced diameter, a similar interpretation is shown in Figure 8.70(b). An alternative method applying to steep internal tapers is shown in Figure 8.71. NOTE: With this method it may be necessary in special cases to specify a control on circularity errors at all sections of the cones (see Clause 8.11.4.4). COPYRIGHT Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) AS 1100.101—1992 134 FIGURE 8.60 INTERPRETATION OF TOLERANCED CENTRE DISTANCES WITH DATUM SYMBOL COPYRIGHT Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) 135 COPYRIGHT AS 1100.101—1992 FIGURE 8.62 DIMENSIONING POSITIONS BY TOLERANCED CENTRE DISTANCES Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) AS 1100.101—1992 136 FIGURE 8.63 CUMULATIVE ANGULAR TOLERANCING COPYRIGHT Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) 137 AS 1100.101—1992 FIGURE 8.66 BASIC TAPER (OR BASIC ANGLE) METHOD USING A DATUM LENGTH AND TOLERANCED WIDTH COPYRIGHT Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) AS 1100.101—1992 138 FIGURE 8.69 TOLERANCED TAPER METHOD — USING A DATUM LENGTH AND TOLERANCED DIAMETER COPYRIGHT Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) 139 AS 1100.101—1992 FIGURE 8.71 TOLERANCED ANGLE METHOD — FOR STEEP INTERNAL TAPER 8.3.13.4 Fitting to gauge or mating part Where it is necessary to specify that a tapered surface must fit a gauge, or another component, notes such as those shown in Figures 8.72 and 8.73 should be used. Whenever this method of specification is used, instruction as to the method of inspection should be included to ensure that the functional requirements are met. 8.3.13.5 Three toleranced dimensions method The method of dimensioning tapers shown in Figure 8.74 may be adopted where the diameter at each end and the length are all toleranced. NOTE: This method is not recommended for precision tapers since it introduces an accumulation of tolerances. It may be used for castings, forgings, sheet metal work, and other non-functional tapers. COPYRIGHT Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) AS 1100.101—1992 140 FIGURE 8.74 DIMENSIONING TAPERS BY THREE TOLERANCED DIMENSIONS METHOD COPYRIGHT 141 AS 1100.101—1992 8.3.14 Radii with unlocated centres Radii with unlocated centres shall be toleranced by one of the methods in Clause 8.3.8.1. The interpretation of toleranced radii, where both upper and lower limits of size are given as in Figure 8.75(a), is shown in Figure 8.75(b). Provided that the actual profile lies within the tolerance zone defined by the upper and lower limits of size, the profile is acceptable. Where only the low limit of size is given as in Figure 8.76(a), any profile is acceptable, provided that it does not become smaller than the radius specified in Figure 8.76(b). Where only the high limit of size is given as in Figure 8.76(a), any profile is acceptable, provided that it lies within the zone represented by R0 and R5 as shown in Figure 8.77(b). In any of the above cases, where it is essential that the radius represent a smooth transition from one point to another, this shall be indicated by a note, such as ‘BLEND’ as shown in Figure 8.78(a). The interpretation of this requirement is shown in Figure 8.78(b) where the actual profile must be contained within the zone defined by the upper and lower limits of size. Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) NOTE: If the form of the radius is critical, this should be specified by additional notes. COPYRIGHT Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) AS 1100.101—1992 142 FIGURE 8.79 TOLERANCE ZONES AND POINTS OF DISCONTINUITY 8.3.15 Profile and curved surfaces — tolerancing and interpretation The form of a profile shall be toleranced by one of the following methods: (a) Where the profile is specified by coordinates, cartesian or polar, including over a replica of a follower, basic dimensions can be arranged to the abscissae or angle and toleranced dimensions to the ordinates or radii respectively (see Figures 8.80 to 8.83). (b) Assigning geometry tolerancing as specified in Clause 8.4. If the controlled profile includes a sharp corner, the corner represents a discontinuity of the tolerance boundary and the boundary is considered to extend to the intersection of the boundary lines as shown in Figure 8.79. At such corners the tolerance zone will permit considerable rounding of the corner. If this is undesirable, the drawing shall indicate the design requirement by specifying the maximum or minimum acceptable radius (or both). NOTE: One important difference between the two methods is that the geometry tolerancing method provides a uniform material tolerance normal to the profile, whereas in the toleranced ordinate method, the material tolerance normal to the surface will vary with the shape of the profile. 8.4 DIMENSIONING AND TOLERANCING AND RELATED PRINCIPLES — GEOMETRY 8.4.1 General This Clause establishes the terminology and practices for expressing tolerances of form, orientation, and location in conjunction with the relevant dimensions of particular features. Such tolerances are termed geometry tolerances. 8.4.2 Terminology 8.4.2.1 Datum group — a group of datums of an item which serves as a reference for the location of other features on the item. (See Figure 8.84.) 8.4.2.2 Datum system — a system which consists of mating datum groups. COPYRIGHT Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) 143 FIGURE 8.81 TOLERANCED ORDINATES OVER FOLLOWER COPYRIGHT AS 1100.101—1992 Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) AS 1100.101—1992 144 FIGURE 8.83 TOLERANCED RADII OVER FOLLOWER COPYRIGHT Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) 145 AS 1100.101—1992 FIGURE 8.84 DATUM GROUP ESTABLISHED BY TWO FEATURES, A AND B 8.4.2.3 Geometric reference frame — a diagrammatic representation of the perfect geometric relationship between perfect features, including datums, in a group. See Figure 8.86(b) which shows the geometric reference frame for group 2 of the component of Figure 8.86(a). 8.4.2.4 Least material condition — the state of the considered feature wherein it is everywhere at the least material size specified on the drawing. 8.4.2.5 Maximum material condition — the state of the considered feature wherein it is everywhere at the maximum material size specified on the drawing. (See Figure 8.85.) 8.4.2.6 Virtual condition (a) Of a feature — the limiting functional boundary permitted by the drawing data, which is generated by the collective effect of the maximum material size of the considered feature and the specified geometry tolerances. (b) Of a group of features — the assembly of the virtual condition of all the features comprising the group in perfect geometric relationship as defined by the drawing data. 8.4.2.7 Virtual size — the dimension defining the virtual condition of a feature. (See Figure 8.85.) 8.4.2.8 Tolerance diagram — the geometric reference frame with the tolerance zones superimposed upon it. (See Figure 8.86(c).) 8.4.2.9 Tolerance, form — the total amount of variation permitted for the form of a feature. 8.4.2.10 Tolerance, geometry — the maximum permissible overall variations of form, location and orientation of a feature. 8.4.2.11 Tolerance, position — the total amount of variation permitted for the location of a feature in the group of which it is a member. COPYRIGHT AS 1100.101—1992 146 Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) FIGURE 8.85 RELATIONSHIP BETWEEN VARIOUS SIZES AND CONDITIONS 8.4.3 Symbols 8.4.3.1 General This Clause establishes the symbols for specifying geometry tolerances on engineering drawings. 8.4.3.2 Symbol construction Information related to the construction, form, and proportions of individual symbols described herein is contained in Clause 4.3. 8.4.3.3 Geometric characteristic symbols The symbols denoting geometric characteristics are shown in Table 8.2. TABLE 8.2 SYMBOLS FOR GEOMETRIC CHARACTERISTICS Application For individual features Type of tolerance Form Characteristic Straightness Flatness Circularity (roundness) Cylindricity For individual or related features Profile Profile of a line Profile of a surface For related features Orientation Angularity Perpendicularity Perallelism Location Position including concentricity and symmetry Runout Circular runout Total runout COPYRIGHT Symbol Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) 147 FIGURE 8.86 LOCATION OF FEATURE PATTERNS COPYRIGHT AS 1100.101—1992 AS 1100.101—1992 148 8.4.4 Specification of geometry tolerances 8.4.4.1 Methods of specification Geometry tolerances shall be specified on drawings using either the tolerance frame or tabular method. 8.4.4.2 Geometry tolerance frame Geometric characteristic symbols, the tolerance value, and datum reference letters, where applicable, are combined using the tolerance frame method (see Figure 8.87) or the tabular method (see Figure 8.88) to express a geometric tolerance. Tolerance frame method is preferred when there are no more than three simple groups. Tabular method is preferred when the group or groups are complex or number three or more. Examples of display using the tabular presentation and the tolerance frame method are shown in Appendix B. 8.4.4.3 Tolerance frame method An example of a tolerance frame is shown in Figure 8.87. Each tolerance frame shall be located so that it can be read from the bottom of the drawing and the details listed in Clauses 8.4.4.3 to 8.4.4.5 should be given. (See also Appendix B.) Where it is necessary to identify groups in a drawing, they shall be identified by inserting a number in the left-hand compartment as shown in Figure 8.87. Where it is not necessary to identify a feature with a group, the left-hand compartment shall be omitted. (See example in Figure 8.97.) Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) FIGURE 8.87 TOLERANCE FRAME DISPLAY The feature controlled by the tolerance frame shall be indicated by one of the following methods: (a) A leader connecting it to either end of the tolerance frame. The leader shall terminate in an arrowhead at the toleranced feature. (See Figure 8.89.) (b) (i) The feature identification symbol and letter shall be placed adjacent to the tolerance frame controlling the feature as in Figure 8.108 or shown separate from the tolerance frame as in Figure 8.109. (ii) A leader connecting it to the feature identification symbol in which is inscribed an appropriate identification letter. The leader shall terminate in an arrowhead at the toleranced feature. (See Figure 8.90). The arrowhead shall be positioned as follows: (A) On the outline of the feature or on an extension of the outline (but not at a dimension line) when the tolerance refers to the line itself or to the surface represented by the line (see Figure 8.89(a)). (B) On a projection line at a dimension line when the tolerance refers only to the axis or median plane of the feature so dimensioned (see Figures 8.89(b) and (c)). (C) On the axis or median plane when the tolerance refers to the common axis or median plane of all features on the axis or median plane (see Figures 8.89(d), (e), and (f)). NOTE: Figure 8.89(b) and (d) show alternative methods of expressing the same requirement on a single feature part; however, for multiple feature parts there can be distinction as shown in Item C of Table 8.7. 8.4.4.4 Symbol Symbols indicating the characteristics to be toleranced shall conform to those in Figure 4.14 and shall be inscribed in the appropriate compartment of the tolerance frame. 8.4.4.5 Tolerance value The required tolerance value shall be inserted in the appropriate compartment of the frame subject to the following condition: (a) If the tolerance zone is neither circular nor cylindrical, its width lies in the direction of the arrow terminating the leaders (see Table 8.14, Parallelism 1(a) and (b)). (b) If the tolerance zone is cylindrical, the tolerance value shall be preceded by the symbol ∅ (c) If the tolerance is applied to a specified length, lying anywhere, the value of this length shall be added after the tolerance value, and separated from it by an oblique stroke (see Figure 8.91). (d) For a surface, the indication in Figure 8.91 is used for a surface. This means that the tolerance applies to all lines of the specified length in any position and any direction. COPYRIGHT Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) 149 FIGURE 8.89 INDICATION OF FEATURE CONTROLLED COPYRIGHT AS 1100.101—1992 AS 1100.101—1992 150 Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) (e) If, to the tolerance of the whole feature, another tolerance of the same type restricted to a specified length is added, the latter tolerance shall be indicated below the former as shown in Figure 8.92. (f) If the tolerance is applied only to a specified portion within the feature, this portion shall be shown by a Type J line and dimensioned as shown in Figure 8.93. FIGURE 8.93 TOLERANCE OVER A SPECIFIED PORTION COPYRIGHT 151 AS 1100.101—1992 (g) If the tolerance is applied to a specified length projected beyond the feature, this length shall be shown by a Type J line and dimensioned, as illustrated in Figure 8.94 (see also Clause 8.10.10). FIGURE 8.94 PROJECTED TOLERANCE ZONE INDICATION Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) (h) If the maximum material modifier is to be applied, then it shall be positioned in the frame as follows: (i) After the tolerance value if the principle of maximum material condition is to be applied to the toleranced feature (see Figure 8.95(a)). (ii) After the letter identifying the datum if the principle of maximum material condition is to be applied to the datum (see Figure 8.95(b)). (iii) After both the tolerance value and the letter identifying the datum if the principle of maximum material condition is to be applied both to the toleranced feature and to the datum (see Figure 8.95(c)). Unless indicated by the symbol , a geometry tolerance applies regardless of feature size. FIGURE 8.95 EXAMPLES OF THE USE OF (i) Information relating to the number, dimension, and tolerance of a feature should be placed above its tolerance frame as in Figure 8.96. Notes relating to the feature should be inscribed below the tolerance frame. FIGURE 8.96 INFORMATION ASSOCIATED WITH A TOLERANCE FRAME COPYRIGHT AS 1100.101—1992 152 (j) If, to the tolerance of the whole feature at MMC, another tolerance of the same type restricts the permissible error at other than MMC, the latter tolerance shall be indicated below the former as shown in Figure 8.97. Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) FIGURE 8.97 RESTRICTED TOLERANCE AT OTHER THAN MMC 8.4.4.6 Datum feature The datum identification letter shall be inserted in the last compartment of the tolerance frame (see Figure 8.100(d)). Where a single datum is established by two features, a hyphen shall be placed between the letter designating the features (see Figure 8.109). Where a datum system is established by — (a) two features only, the two identifying letters of the datum features shall be inserted in the following order: primary, secondary (see Figure 8.110); and (b) a group of features, the group number shall be used to identify the datum (see Figure 8.114). Where no datum is applicable as shown in Figure 8.98, or where a datum is the geometric reference frame for the group and is not related to any other feature, the right-hand compartment shall be omitted. See Figure 8.99. Alternatively, the datum feature may be indicated as shown in Figure 8.100. FIGURE 8.98 DATUM NOT APPLICABLE 8.4.5 Tabular method 8.4.5.1 General Examples of tabular presentations are shown in Figure 8.88. The table should be located in a prominent position on the drawing and the details listed in this Clause should be given. 8.4.5.2 Group number Where it is necessary to identify groups in a drawing, they shall be identified by inserting a number in the first column of the table as shown in Figure 8.88. When it is not necessary to identify a feature with a group, a complete diagonal line shall be inserted in the first column as shown in Figure 8.101. COPYRIGHT Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) 153 FIGURE 8.100 INDICATION OF DATUMS COPYRIGHT AS 1100.101—1992 AS 1100.101—1992 154 8.4.5.3 Feature controlled The feature controlled by the tolerance shall be indicated by — (a) the method detailed in Clause 8.4.4.3(b)(i); and (b) the feature identification letter inscribed on the appropriate line in the second column of the table (see Figure 8.88). 8.4.5.4 Number of features The number of features corresponding to each identifying letter shall be entered in the appropriate column of the table. 8.4.5.5 Symbol Symbols indicating the characteristics to be toleranced shall conform to those in Figure 4.14, and shall be inscribed in the appropriate column of the table. 8.4.5.6 Tolerance value The required tolerance value shall be inserted in the appropriate column of the table with the provisions detailed in Clause 8.4.4.4. Tolerances over a specified length should be indicated as shown in Figure 8.101. Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) FIGURE 8.101 TOLERANCE OVER A SPECIFIED LENGTH — TABULAR METHOD 8.4.5.7 Datum features The datum feature identification letter shall be inserted in the last column of the table (see Figure 8.88). The significance of the position of the datum symbol is the same as for the arrowhead detailed in Clause 8.4.4.2 and Figure 8.89. Where a single datum is established by two features, a hyphen shall be placed between the letters designating the features (see Figure 8.88, Group 4). Where a datum system is established by two features only, the two identifying letters of the datum features are inserted in the following order: primary, secondary (see Figure 8.88, Group 5). Where a datum system is established by a group of features, the group number shall be used to identify the datum (see Figure 8.88, Group 2). Where no datum is applicable as illustrated in Figure 8.98 or where a datum is the geometric reference frame for the group and is not related to any other feature as illustrated in Figure 8.102, a completed diagonal line shall be inserted in the appropriate column of the table. 8.4.5.8 Symbol The symbol shall be indicated as detailed in Clause 8.3.6. Where the principle of maximum material condition applies to all features or to all datums or to all features and datums, the modifier may be placed in the appropriate headings of the table and omitted from the body of the table (see Figure 8.103). FIGURE 8.102 GEOMETRIC REFERENCE FRAME AS DATUM COPYRIGHT 155 AS 1100.101—1992 FIGURE 8.103 MODIFIER APPLICABLE TO ALL FEATURES — TABULAR DISPLAY 8.5 INTERPRETATION OF MAXIMUM MATERIAL CONDITION Where a geometric tolerance is applied on an MMC basis, the specified tolerance is dependent on the size of the considered feature. The tolerance is limited to the specified value if the feature is produced at its MMC limit of size. Where the actual size of the feature has departed from MMC, an increase in the tolerance is allowed equal to the amount of such departure. The total permissible variation in the specific geometric characteristic is maximum when the feature is at least material condition. (See Figure 8.122 and Appendix E for application.) NOTES: 1 Zero geometry tolerances can only be associated with the maximum material condition as to do otherwise would be to demand perfection. 2 Where a geometric tolerance is applied without reference to LMC or MMC the specified tolerance is independent of the size of the considered feature. The tolerance is limited to the specified value regardless of the actual size of the feature. Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) 3 Since the maximum material principle involves a relationship between size and geometry form or position, it can only be applied to those features where this relationship is possible. In effect this limits its application to features incorporating an axis or median plane. See Table 8.3. 8.6 DATUM SPECIFICATION AND INTERPRETATION 8.6.1 General This Clause deals with the constituent parts of the geometric reference frame, which is used to establish the true positions of all features which are to be regarded as members of the one group, including all datum and non-datum features. It contains the criteria for selecting, designating, and using features of a part as grouped datum features in the geometrical reference frame, and establishes the origins of the dimensional relationships between non-datum and datum features. The group of datum features alone establishes a datum reference frame within the geometric reference frame. 8.6.2 The function, designation, and interpretation of datums Datums are used for the following purposes: (a) To align certain features on two components in accurate geometric relation when assembled. (b) To locate mating components accurately to facilitate assembly. (c) To act as a convenient base from which to dimension features. Component features are referred to as datum features, such as datum holes, datum pins, datum surfaces, whereas the geometric counterparts with which they are associated are called datum axes, datum planes, datum points, or datum lines. Since measurements cannot be made from the geometric counterparts, the datum planes and axes of the geometric reference frame are represented in practice by the precise surfaces and axes of the manufacturing and inspection equipment. Machine tables and surface plates are not true planes, nor do the spindles of dividing heads rotate about precisely true axes, but they are usually of such high accuracy that they simulate datum planes and axes adequately. Measurements are therefore made in practice from surfaces and axes in the processing or measuring equipment. Such measurements do not take into account any variations of the datum features from their true positions in the geometric reference frame. 8.6.3 Datum reference frame Sufficient datum features are first chosen on the part from an analysis of assembly and functional requirements, and these chosen features are then used to relate the part to the three mutually perpendicular planes which make up the datum reference frame. This reference frame exists in theory only and not on the part. Therefore it is necessary to establish a method for simulating the theoretical reference frame from the actual features of the part. This simulation is accomplished by positioning the part on appropriate datum features to relate the part adequately to the reference frame and to restrict motion of the part in relation to it. (See Figures 8.104 and 8.105.) These planes are simulated in a mutually perpendicular relationship to provide direction as well as the origin for the positions of related non-datum features in the geometrical reference frame. Thus, when the part is positioned on the datum reference frame (by physical contact between each datum feature and its counterpart in the associated processing equipment), dimensions of non-datum features which are related to the datum reference frame are thereby also mutually perpendicular. This theoretical reference frame constitutes the three-plane dimensioning system used for datum referencing. (See Figure 8.106.) In some cases, e.g. for a single group of features, one datum reference frame will suffice. However, where several groups of features are present, a corresponding number of datum reference frames will be necessary at specific locations on the part. In such cases, each feature control frame must contain the datum feature or datum group references that are applicable. COPYRIGHT AS 1100.101—1992 156 TABLE 8.3 APPLICATION OF MMC Characteristic tolerance The MMC concept may be applied. If indicated below, to the feature being toleranced, or the datum feature (or both) according to the design requirement Straightness Parallelism Perpendicularity Angularity YES for the axis or median plane of a feature, the size of which is specified by a toleranced dimension, e.g. the axis of a hole or a shat of the median plane of a slot NO for a plane surface or a line on a surface Position (includes concentricity and symmetry Flatness Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) Circularity Cylindricity No for all features Profile of a line Profile of a surface Run-out Total run-out 8.6.4 Datum features 8.6.4.1 General Datum features are selected, singly or in groups, on the basis of function as explained in Clause 8.6.1. Corresponding features are also selected on mating parts to establish datum systems for the two parts. Datum features must be readily discernible on each part. Therefore, for symmetrical parts or parts with identical features, physical identification of the datum features on the part may be necessary. A datum feature should be accessible on the part and be of sufficient size to permit subsequent processing operations. 8.6.4.2 Temporary and permanent datum features Selected datum features of castings, forgings, or weldments may be used temporarily for the establishment of machined surfaces which will serve subsequently as permanent datum features. Such temporary datum features may or may not be subsequently removed by machining. Permanent datum features should be surfaces or diameters not appreciably changed by subsequent machining operations. COPYRIGHT 157 AS 1100.101—1992 8.6.4.3 Datum feature symbols Datum features are identified on the drawing by means of symbols. These symbols relate to physical features and are not applied to centre-lines, centre planes, or axes. 8.6.4.4 Datum feature control Measurements made from a datum plane do not take into account any variations of the datum surface from the datum plane. Consideration shall be given to the desired accuracy of datum features relative to design requirements and the degree of control necessary for the non-datum features related to them. In general, datum features will need to be controlled by specifying appropriate geometry tolerances. Where control of the entire feature becomes impractical, use of datum targets may be considered. (See Clause 8.6.6.) Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) FIGURE 8.104 PART A LOCATED ON PART B BY THREE PLANE SURFACES 8.6.5 Examples of datums and datum groups Examples of datums and datum groups are as follows: (a) Single datum established by one feature The simplest datum consists of one feature such as a hole, a pin, or a surface. In Figure 8.107(a), the axis of the bore Z at MMC is the datum for the concentricity of the external diameter Y. The geometric reference frame consists of a straight line corresponding to the axes of both Z and Y which are coincident, and the MMC tolerance diagram which is the geometric reference frame with the tolerance zones added, is shown in Figure 8.107(b). In Figure 8.108(a), the surface X is datum for the position of the three holes W. The geometric reference frame here consists of a datum plane, of width and length corresponding to surface X, and three lines corresponding to the axes of the three holes W situated at their correct positions relative to each other and to X. The MMC tolerance diagram is shown in Figure 8.108(b). Where no flatness tolerance is specified for the datum surface, the tolerance zone for the plane established by that surface is indicated in the tolerance diagram as being of zero width as shown in Figure 8.108(b). NOTES: 1 It should be realized that the actual surface will not be perfectly flat. 2 Screw threads, gears, and splines. Where a screw thread is specified as a datum reference, the datum axis is derived from the pitch cylinder, unless otherwise specified. Where a gear or spline is specified as a datum reference, a specific feature of the gear or spline must be designated to derive a datum axis. In general, these types of datum features should be avoided. (b) Single datum established by two features Two features such as two coaxial holes or shafts may be used to establish a single common datum axis as illustrated in Figure 8.109(a). Where no concentricity tolerance is specified for the two datum features, the tolerance zone for their axes are indicated in the tolerance diagram as being of zero diameter as shown in Figure 8.109(b). NOTES: 1 It should be realized that the actual axes will not be perfectly coaxial. 2 This method is applicable when the lengths of the datum features are short relative to their distance apart. (c) Datum group established by two features Two features such as a hole and a surface, or a spigot and a surface may be selected to establish a datum group. In Figure 8.110(a), the datum features surface A and recess B form a single datum group. The features within the datum group are toleranced for geometric relation in a similar way to non-datum features. The interpretation of Figure 8.110(a) is that surface A is the principal datum, and that the datum recess B has a zero tolerance for squareness at MMC with respect to A. The shaft C is required to be square to A and concentric with B within the tolerance zone of ∅ 0.04 when C and B are both at their maximum material condition as indicated in the geometry tolerance frame in Figure 8.110(b). COPYRIGHT Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) AS 1100.101—1992 158 FIGURE 8.106 RESULTING DATUM REFERENCE FRAME FOR PART A COPYRIGHT 159 AS 1100.101—1992 Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) FIGURE 8.107 SINGLE DATUM ESTABLISHED BY AN AXIS In Figure 8.111(a), the flat surface K and the cylinder J form a datum group for the four holes L. The geometric reference frame consists of a datum plane corresponding to datum surface K, a datum axis square to the datum plane corresponding to the axis of the datum cylinder J, and the four axes of the holes L in correct position relative to the datum plane and axis and to each other. The four holes L have position tolerances of ∅ 0.25 at MMC in relation to the datum group. The tolerance diagram for this group at MMC is indicated in Figure 8.111(b), where K is a primary datum with a flatness tolerance of 0.05 width and J has a zero squareness tolerance at MMC with respect to K. (d) Datum group established by three features Three features may be selected to form more complex datum groups and they are then toleranced for geometry with respect to their true positions in a similar way to the datum features of Figure 8.111(a). The true positions of the datum features are located relative to the three mutually perpendicular planes or axes of the geometric reference frame. For example, the tolerance diagram for Group 2 in Figure 8.112 which includes the datum Group 1, is the geometric reference frame with the tolerance zones superimposed as shown in Figure 8.113. The datum surface A in Figure 8.112 must satisfy the specified tolerance for flatness, and the datum surfaces B and C must also satisfy the specified tolerances for squareness. Since all three are grouped, their surfaces must simultaneously fall within the tolerance zones shown in Figure 8.113. The axes of the two holes D must be contained within cylinders 0.25 mm diameter; with their axes in the specified true positions in relation to the datum planes A, B and C (see Figure 8.113). The three datum surfaces may be classified into primary, secondary, and tertiary, depending on their relative functional importance, which in turn determines the relative magnitude of the tolerances. In Figure 8.112 the datum group consists of the primary datum surface A, the secondary datum surface B and the tertiary datum surface C. The primary datum surface is indicated in the extreme right-hand column of the tables and the order of importance of the other two surfaces may be inferred from the magnitude of the squareness tolerances. The corresponding three planes of the geometric reference frame are indicated in Figure 8.113. A further example is indicated in Figure 8.114. 8.6.6 Datum targets 8.6.6.1 General Datum targets are shown on the drawing by means of a datum target symbol (see Clause 8.3.3.5). They indicate specific points, lines, or areas of contact on a part that are used in establishing a datum reference frame. Because of inherent irregularities, the entire surface of some features cannot be effectively used to establish a datum. Examples are non-planar or uneven surfaces produced by casting, forging, or moulding; surfaces of weldments; and thin section surfaces subject to bowing, warping, or other inherent or induced distortions. COPYRIGHT Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) AS 1100.101—1992 160 FIGURE 8.108 SINGLE DATUM ESTABLISHED BY A SURFACE 8.6.6.2 Datum target points A datum target point is indicated by the symbol X, which is dimensionally located on a direct view of the surface. Where there is no direct view, the point location is dimensioned on two adjacent views (see Figure 8.115). 8.6.6.3 Datum target lines A datum target line is indicated by the symbol X on an edge view of the surface, a line type K on the direct view, or both (see Figure 8.116). Where the length of the datum target line must be controlled, its length and location are dimensioned. 8.6.6.4 Datum target areas Where it is determined that an area or areas of flat contact is necessary to assure establishment of the datum (that is, where spherical or pointed pins would be inadequate), a target area of the desired shape is specified. The boundary of the datum target area is drawn with a line type K and the area is cross-hatched as shown in Figure 8.117. Where it becomes impractical to delineate a circular target area, the method of indication shown in Figure 8.117(b) may be used. COPYRIGHT Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) 161 AS 1100.101—1992 FIGURE 8.109 SINGLE DATUM ESTABLISHED BY TWO FEATURES 8.6.6.5 Datum target dimensions The location and size, where applicable, of datum targets are defined with appropriate dimensions as shown in Figure 8.118. In this example, three mutually perpendicular planes are established by three target points on the primary datum feature, two on the secondary, and one on the tertiary. 8.7 VIRTUAL CONDITION Depending upon its function, a feature is controlled by tolerances such as size, form, orientation, and location with or without MMC or envelope modifiers as applicable. Consideration should be given to the collective effect of these factors in determining the clearance between mating parts and in establishing gauge feature sizes. From such consideration, a net resultant boundary is derived, termed virtual condition (see Clause 8.4.2.6 and Appendix E). 8.8 SCREW THREADS — ORIENTATION AND LOCATION Each tolerance of orientation or location and datum reference specified for a screw thread applies to the axis of the thread derived from the pitch cylinder. Where an exception to this practice is necessary, the specific feature of the screw thread (such as MINOR DIA or MAJOR DIA) shall be stated above the feature control frame. COPYRIGHT Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) AS 1100.101—1992 162 FIGURE 8.110 DATUM GROUP ESTABLISHED BY TWO FEATURES — EXAMPLE 1 COPYRIGHT Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) 163 COPYRIGHT AS 1100.101—1992 FIGURE 8.111 DATUM GROUP ESTABLISHED BY TWO FEATURES — EXAMPLE 2 Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) AS 1100.101—1992 164 FIGURE 8.112 DATUM GROUP ESTABLISHED BY THREE SURFACES COPYRIGHT Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) 165 AS 1100.101—1992 FIGURE 8.113 MMC TOLERANCE DIAGRAM FOR GROUP 2 OF FIGURE 8.112 8.9 GEARS AND SPLINES — ORIENTATION AND LOCATION Each tolerance of orientation or location and datum reference specified for gears and splines shall designate the specific feature of the gear or spline to which each applies (such as MAJOR DIA, PITCH DIA or MINOR DIA). This information is stated above the feature control frame. 8.10 TOLERANCES OF POSITION 8.10.1 General Tolerances of position are used to control the following relationships: (a) Centre distance between such features as holes, slots, bosses and tabs. (b) Location of features (such as in Item (a)) as a group, from datum features such as plane and cylindrical surfaces. (c) Concentricity or symmetry of features. (d) Features with centre distances equally disposed about a datum axis or plane. COPYRIGHT Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) AS 1100.101—1992 166 FIGURE 8.114 DATUM GROUP ESTABLISHED BY A SURFACE AND TWO HOLES COPYRIGHT Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) 167 AS 1100.101—1992 FIGURE 8.116 DATUM TARGET LINE 8.10.2 Position tolerancing A position tolerance defines a zone within which the centre, axis, or median plane of a feature of size is permitted to vary from true (theoretically exact) position. Basic dimensions establish the true position from specified datum features and between interrelated features. A position tolerance is indicated by the position symbol, a tolerance, and appropriate datum references placed in a feature control frame. 8.10.3 Tolerances of position with true position dimension (see Table 8.4) A tolerance of position limits the deviation of the position of a feature from its specified true position. The tolerance zone is symmetrically located about the true position of a point, line or plane and may be the area within a circle or between two parallel straight lines or the space within a cylinder or between two parallel planes. Where the tolerance zone is the space within a cylinder or between two parallel planes, the axis of the cylinder or the two parallel planes shall be normal to the plane of projection. COPYRIGHT Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) AS 1100.101—1992 168 8.10.4 Tolerances of position applied to concentricity (see Table 8.5) A concentricity tolerance is a particular case of a position tolerance in which the position of a feature is specified by its concentricity relationship. 8.10.5 Tolerances of position applied to symmetry (see Table 8.6) A symmetry tolerance is a particular case of a position tolerance in which the position of the feature is specified by its symmetrical relationship. 8.10.6 Material condition basis Position tolerancing may be applied on an MMC or regardless of feature size basis. The symbol for MMC follows the specified tolerance and applicable datum reference in the tolerance frame when required (see Figure 8.123). Where no symbol for MMC is shown, the specified position tolerance applies regardless of the size of the feature. COPYRIGHT Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) 169 COPYRIGHT AS 1100.101—1992 TABLE 8.4 TOLERANCES OF POSITION (continued) Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) AS 1100.101—1992 170 TABLE 8.4 (continued) COPYRIGHT Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) 171 TABLE 8.5 TOLERANCES OF POSITION APPLIED TO CONCENTRICITY COPYRIGHT AS 1100.101—1992 Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) AS 1100.101—1992 172 TABLE 8.6 TOLERANCES OF SYMMETRY COPYRIGHT 173 AS 1100.101—1992 Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) 8.10.7 MMC as related to position tolerancing The position tolerance and maximum material condition of mating features are considered in relation to each other. MMC by itself means a feature of a finished product contains the maximum amount of material permitted by the toleranced size dimension for that feature. Thus, for holes, slots, and other internal features, maximum material is the condition where these features are at their minimum allowable sizes. For shafts, as well as for bosses, lugs, tabs, and other external features, maximum material is the condition where these are at their maximum allowable sizes. A position tolerance applied at MMC may be explained in any of the following ways: (a) In terms of the surface of a hole Although the specified size limits of the hole shall be maintained, no element of the hole surface shall be inside a theoretical boundary located at true position (see Figure 8.119). (b) In terms of the axis of a hole Where a hole is at MMC (minimum diameter), its axis must fall within a cylindrical tolerance zone whose axis is located at true position. The diameter of this zone is equal to the position tolerance (see Figure 8.120(a) and (b)). This tolerance zone also defines the limits of variation in the orientation of the axis of the hole in relation to the datum surface (see Figure 8.120(c)). (c) It is only when the feature is at MMC that the specified position tolerance applies. Where the actual size of the feature is larger than MMC, additional position tolerance results (see Figure 8.121). This increase of position tolerance is equal to the difference between the specified maximum material limit of size (MMC) and the actual size of the feature. The specified position tolerance for a feature may be exceeded where the actual size is larger than MMC and still satisfy functional and interchangeability requirements. FIGURE 8.119 BOUNDARY FOR SURFACE OF HOLE AT MMC In many instances, a group of features (such as a group of mounting holes) shall be positioned relative to a datum feature at MMC. See Figure 8.122. Where datum feature B is at MMC, its axis determines the position of the pattern of features as a group. Where datum feature B departs from MMC, its axis may be displaced relative to the position of the datum axis (datum B at MMC) in an amount equal to one-half the difference between its actual and MMC sizes. If a functional gauge is used to check the part, this shift of the axis of the datum feature is automatically accommodated. However, if open set-up inspection methods are used to check the position of the feature pattern relative to the actual axis of the actual datum feature, this shall be taken into account. Since the actual datum feature must serve as the origin of measurements for the pattern of features, the features are therefore viewed as if they, as a group, had been displaced relative to the axis of the (actual) datum feature. This relative shift of the pattern of features, as a group, with respect to the axis of the datum feature does not affect the positional tolerances of the features relative to one another within the pattern. COPYRIGHT Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) AS 1100.101—1992 174 FIGURE 8.120 HOLE AXES IN RELATION TO POSITION TOLERANCE ZONES 8.10.8 Zero position tolerancing at MMC In the preceding explanation, a position tolerance of some magnitude is specified for the position of features. Zero position tolerances may be specified (see Clause 8.11.10 for details). 8.10.9 Location of feature patterns 8.10.9.1 General Differing functional requirements for the location of feature patterns require different methods of assigning tolerances and of displaying these clearly on drawings. The features within the pattern are normally located by position tolerances as shown in Figures 8.123 to 8.128 (inclusive) and the pattern itself is usually located with respect to chosen external features either by toleranced centre distances as shown in Figures 8.123, 8.125, 8.127 and 8.128 or by position tolerances as shown in Figures 8.124 and 8.126. The general principle adopted in the examples is that where toleranced centre distances are used to locate a group of features, each centre distance requirement and each group positional requirement shall be satisfied independently (see Clause 8.3.4). The exclusive use of toleranced centre distances to locate all features in a pattern is not recommended due to difficulties brought about by accumulation of tolerances. The following notes apply to Figures 8.123, 8.125, 8.127, and 8.128: (a) It should be noted that surfaces X and Y, although shown at right-angles, will not necessarily be precisely so in practice. (b) Where locations of features are directly controlled by toleranced centre distances, the surfaces X and Y in the tolerance diagrams shall be of sufficient length to span those features. COPYRIGHT Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) 175 FIGURE 8.122 DATUM FEATURE AT MMC COPYRIGHT AS 1100.101—1992 Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) AS 1100.101—1992 176 8.10.9.2 Examples Example 1 Figure 8.123 is the most common and the simplest case in which the feature pattern is located by toleranced centre distances. There are three requirements which shall be satisfied independently. These are as follows: (a) The actual positional relationship of the axes of the four grouped holes shall conform to the tolerance diagram shown in Figure 8.123(b). (b) The actual axes of the two lower holes shall conform to the tolerance diagram Figure 8.123(c). (c) The actual axes of the two left-hand holes shall conform to the tolerance diagram Figure 8.123(d). Orientation of the pattern of holes with respect to surfaces X and Y is controlled by the centre distance tolerances. Examples 2 and 3 The orientation of the pattern of holes with respect to the external surfaces is controlled in both examples shown in Figures 8.124 and 8.125 but in different ways, i.e. by position tolerances in Figure 8.124(a) and by centre distances tolerances in Figure 8.125(a). In Figure 8.124(a) the group of five holes is located relative to the datum Group 2, consisting of the surfaces A, B and C. Group 3 consist of five holes and the datum frame. The geometric reference frame for Group 3 is shown in Figure 8.124(b) and the tolerance diagram in Figure 8.124(c). The three requirements for location contained in Figure 8.125(a) shall be satisfied independently and these are indicated in Figure 8.125(b) to (d). Examples 4 and 5 In Figures 8.126 and 8.127 the orientation of the pattern of holes relative to the external surfaces is not controlled by either method of dimensioning and tolerancing. In Figure 8.126(a), Group 2 consists of the three external surfaces A, B and C; Group 2 includes hole D and Group 2 as datum; and Group 4 contains the four holes ∅ 8 with the hole D and surface A as datums. The tolerance diagrams (which include the geometric reference frames) for Groups 3 and 4 are shown in Figure 8.126(b) and (c) respectively and these tolerance requirements shall be satisfied independently. The three requirements for location of the feature pattern in Figure 8.127(a) shall be satisfied independently and are illustrated in Figure 8.127(b) to (d). Example 6 In Figure 8.128 the axes of the three holes on the vertical centre-line shall lie between two parallel planes as shown in Figure 8.128(c). Likewise, the axes of the three holes on the horizontal centre-line shall lie between two parallel planes as shown in Figure 8.128(d). All three requirements shown in Figure 8.128(b) to (d) shall be complied with independently. 8.10.10 Projected tolerance zone (see Table 8.7) Normally tolerances for position apply over the whole length of a feature. Where it is a functional requirement that the tolerance applies over some other length, not necessarily the length of the feature, the projected tolerance zone concept should be used. This concept shall be indicated on the drawing by the symbol and depicted by a line Type J, parallel and adjacent to the axis or median plane of the feature and the extent of the length over which the tolerance applies indicated by dimensions to each extremity of that line as illustrated in Table 8.7. The projected tolerance zone may be adjacent as in Items 1 and 2(a), remote as in Item 2(b), within and projected as in Item 2(c), both sides as in Item 2(d), or in two directions as in Item 2(e). 8.10.11 Counterbored holes Where position tolerances are used to locate concentric features, such as counterbored holes, the following practices apply: (a) Where position tolerances are used to locate holes and counterbores relative to common datum features, two tolerance frames are used. One tolerance frame is placed under the note specifying the hole requirements (group 1) and the other under the note specifying counterbore requirements (datum being group 1) (see Figure 8.129). Tolerance zones for hole and counterbore are located at true position relative to the specified datums. The tolerance zones for holes and counterbores may be the same or different diameters. (b) Where position tolerances are used to locate holes and also control individual counterbore-to-hole relationships relative to different datum features, two tolerance frames are used, as in Item (a) (see Figure 8.129). 8.10.12 Non-circular features The basic principle of true position dimensioning and position tolerancing for circular features, such as holes and bosses, apply also to non-circular features, such as open-end slots, tabs, and elongated holes. For such features of size, a position tolerance is used to locate the centre plane established by parallel surfaces of the feature. The tolerance value represents a distance between two parallel planes. The diameter symbol is omitted from the feature control frame. Examples are shown in Figures 8.131 and 8.132. 8.10.13 Spherical features A positional tolerance may be used to control the location of a spherical feature relative to other features of a part (see Figure 8.133). The symbol for spherical diameter precedes the size dimension of the feature. Since the feature is spherical, its tolerance zone is likewise spherical, having a diameter equal to the specified position tolerance. COPYRIGHT Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) 177 FIGURE 8.123 LOCATION OF FEATURE PATTERNS — EXAMPLE 1 COPYRIGHT AS 1100.101—1992 Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) AS 1100.101—1992 178 FIGURE 8.124 LOCATION OF FEATURE PATTERNS — EXAMPLE 2 COPYRIGHT Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) 179 FIGURE 8.125 LOCATION OF FEATURE PATTERNS — EXAMPLE 3 COPYRIGHT AS 1100.101—1992 Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) AS 1100.101—1992 180 FIGURE 8.126 LOCATION OF FEATURE PATTERNS — EXAMPLE 4 COPYRIGHT Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) 181 FIGURE 8.127 LOCATION OF FEATURE PATTERNS — EXAMPLE 5 COPYRIGHT AS 1100.101—1992 Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) AS 1100.101—1992 182 FIGURE 8.128 LOCATION OF FEATURE PATTERNS — EXAMPLE 6 COPYRIGHT Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) 183 COPYRIGHT AS 1100.101—1992 TABLE 8.7 PROJECTED TOLERANCE ZONE (continued) Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) AS 1100.101—1992 184 TABLE 8.7 (continued) COPYRIGHT Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) 185 FIGURE 8.129 DIFFERENT POSITION TOLERANCE FOR HOLES AND COUNTERBORES, SAME DATUM REFERENCES COPYRIGHT AS 1100.101—1992 Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) AS 1100.101—1992 186 FIGURE 8.130 POSITION TOLERANCE FOR COUNTERBORES, RELATIVE TO HOLES COPYRIGHT Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) 187 FIGURE 8.131 POSITION TOLERANCING OF SLOTS COPYRIGHT AS 1100.101—1992 Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) AS 1100.101—1992 188 FIGURE 8.132 POSITION TOLERANCING OF ELONGATED HOLES COPYRIGHT Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) 189 COPYRIGHT AS 1100.101—1992 FIGURE 8.133 SPHERICAL FEATURE LOCATED BY POSITION TOLERANCING Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) AS 1100.101—1992 190 8.11 TOLERANCES OF FORM, PROFILE, ORIENTATION, AND RUNOUT 8.11.1 General This Clause establishes the principles and methods of dimensioning and tolerancing to control form, profile, orientation, and runout of various geometrical shapes and free state variations. 8.11.2 Form and orientation control Form tolerances control straightness, flatness, circularity, and cylindricity. Orientation tolerances control angularity, parallelism, and perpendicularity. A profile tolerance may control form, orientation, and size, depending on how it is applied. Tolerances of position control orientation, the extent of this control should be considered before specifying form and orientation tolerances (see Figure 8.120). 8.11.3 Form and orientation tolerance zones A form or orientation tolerance specifies a zone within which the considered feature, its line elements, its axis, or its centre plane must be contained. Where the tolerance value represents the diameter of a cylindrical zone, it is preceded by the diameter symbol. In all other cases, the tolerance value represents a total linear distance between two geometric boundaries and no symbol is required. Certain designs require control over a limited area or length of the surface, rather than control of the total surface. In these instances, the area, or length, and its location are indicated by a Type J line drawn adjacent to the surface with appropriate dimensioning. Where so indicated, the specified tolerance applies within these limits instead of to the total surface. 8.11.4 Form tolerances 8.11.4.1 General Form tolerances are applicable to single (individual) features or elements of single features; therefore, form tolerances are not related to datums. Clauses 8.11.4.2 to 8.11.4.4 cover the particulars of the form tolerances, i.e. straightness, flatness, circularity, and cylindricity. 8.11.4.2 Tolerances of straightness (see Table 8.8) A straightness tolerance may be used to control the following: (a) The straightness of a line on a surface The tolerance zone is the area between two parallel straight lines in the specified plane containing the considered line, and the tolerance value is the distance between the lines. (b) The straightness of an axis (of a feature or a series of features) in a single plane The tolerance zone is the space between two parallel planes normal to the specified plane containing the considered axes, and the tolerance value is the distance between the planes. (c) The straightness in three dimensions of an axis of a feature or features which are solids of revolution The tolerance zone is a cylinder with a diameter equal to the tolerance value. 8.11.4.3 Tolerance of flatness (see Table 8.9) Where a flatness tolerance is used to control the flatness of a surface, the tolerance zone is the space between two parallel planes and the tolerance value is the distance between the planes. The location of the two parallel planes shall be that most favourable acceptance. Flatness may be applied on a unit basis as a means of preventing an abrupt surface variation within a relatively small area of the feature. The unit variation is used either in combination with a specified total variation, or alone. Caution should be exercised when using unit control alone as relatively large variations in flatness can occur unless there is a maximum overall limit specified. Since flatness involves surface area, the size of the unit area, e.g. 25 x 25, is specified to the right of the flatness tolerance, separated by a slash line. For example: 8.11.4.4 Tolerance of circularity (roundness) (see Table 8.10) A circularity tolerance may be used to control the errors of form of a circle in the plane in which it lies. For a solid revolution, the tolerance controls the circularity of the circle formed by the intersection of the surface with a plane. For a cylinder or cone, the plane is perpendicular to the axis, and for a sphere it usually passes through its centre. A circularity tolerance is not concerned with the position of the circle, e.g. its concentricity with a datum axis. For a solid of revolution, the circularity of each cross-section is an individual assessment. A circularity tolerance zone is the annular space between two co-planar circles concentric with each other. The tolerance value is the radial separation of the two circles. The size and location of the circles forming the annular tolerance zone with respect to the considered circle should be that most favourable to acceptance. COPYRIGHT Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) 191 COPYRIGHT AS 1100.101—1992 TABLE 8.8 TOLERANCES OF STRAIGHTNESS (continued) Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) AS 1100.101—1992 192 TABLE 8.8 (continued) COPYRIGHT 193 AS 1100.101—1992 Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) TABLE 8.9 TOLERANCES OF FLATNESS 8.11.4.5 Tolerances of cylindricity (see Table 8.11) Cylindricity is a combination of roundness, straightness and parallelism applied to the surface of a cylinder. The plane (end) surfaces of a cylindrical part are not controlled by a cylindricity tolerance. NOTE: Although the control of roundness, straightness and parallelism by means of cylindricity tolerance may appear to be a convenient technique, the checking of cylindricity in accordance with its definition may present considerable difficulties. It is recommended that the individual characteristics comprising cylindricity be toleranced separately as appropriate to the part concerned. A cylindricity tolerance zone is the annular space between two cylinders coaxial with each other. The tolerance value is the radial separation of the two cylinders. The size and location of the cylinders forming the annular tolerance zone with respect to the considered cylinder should be that most favourable to acceptance. 8.11.5 Tolerances on profiles Profiled surfaces consist of solid figures either having sections of theoretically identical form, e.g. templates, disc cams, or sections of related but not identical form, e.g. aerofoils, drum cams, three-dimensional cams. The ‘profile of a line’ symbol indicates that the tolerance applies to all identical sections of the component or to the particular section designated. The ‘profile of a surface’ symbol indicates that the tolerance applies to the whole of the profiled surface. The tolerance zone associated with the profile symbols is a zone of width equal to the tolerance value normal everywhere to the theoretical profile, and unless otherwise stated shall be equally disposed about that profile (see Table 8.12, Items 1(a) and 2). If a unilateral tolerance zone is required, this shall be clearly indicated on the drawing by a Type J line and a dimension line as in Table 8.12, Item 1(b). NOTE: For information on tolerance zones and points of discontinuity, see Clauses 8.3.14 and 8.3.15. Profiles defined by a combination of circular arcs and straight lines shall be toleranced by indicating all dimensions as basic and the applicable profile tolerance in the tolerance table or frame (see Table 8.12). Profiles defined by cartesian coordinates shall be toleranced by indicating both the abscissae and ordinates as basic dimensions and the applicable profile tolerance in a tolerance table or frame (see Table 8.12). NOTE: For other methods not using geometry tolerance, see Clause 8.3.15. COPYRIGHT Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) AS 1100.101—1992 194 TABLE 8.10 TOLERANCES OF CIRCULARITY COPYRIGHT 195 AS 1100.101—1992 TABLE 8.11 TOLERANCES OF CYLINDRICITY Profiles defined by polar coordinates shall be toleranced by indicating both the angular displacements and appropriate radii or radii over a follower as tangent point dimensions and the applicable profile tolerance in a tolerance table or frame. Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) NOTE: For other methods not using geometry tolerance, see Clause 8.3.15. Three-dimensional profile surfaces shall be toleranced by a combination of one or more of the methods described for: (i) profiles defined by a combination of circular arcs and straight lines, (ii) profiles defined by cartesian coordinates, (iii) profiles defined by polar coordinates, as appropriate to the function of the part. If the theoretical surface is defined by all basic dimensions, and a profile tolerance quoted in the tolerance table or frame, the complete surface shall lie between two surfaces which envelop a series of spheres of diameter equal to the tolerance value with their centres on the theoretical surface (see Table 8.13). If a unilateral tolerance zone is specified, the surfaces of the spheres touch the theoretical surface. 8.11.6 Orientation tolerances 8.11.6.1 General Angularity, parallelism and perpendicularity are orientation tolerances applicable to related features. These tolerances control the orientation of features to one another. 8.11.6.2 Specifying orientation tolerances in relation to datum features In specifying orientation tolerances to control angularity, parallelism and perpendicularity, the considered feature is related to one or more datum features. Relation to more than one datum feature should be considered if required to stabilize the tolerance zone in more than one direction. For a method of referencing datum features (see Clauses 8.4.4.6 and 8.4.5.7, and Table 8.16). Note that angularity, perpendicularity, and parallelism, when applied to plane surfaces, control flatness if a flatness tolerance is not specified. 8.11.7 Tolerances of squareness (See Table 8.14) The toleranced feature may be a line or a surface and the datum feature may be a line or a plane. In general, the tolerance zone is the area between two parallel lines or the space between two parallel planes which are perpendicular to the datum feature and the tolerance value is the distance between the lines or the planes. For a line with respect to a datum plane, the tolerance zone may alternatively be the space within a cylinder of diameter equal to the tolerance value. 8.11.8 Tolerances on parallelism (see Table 8.15) The toleranced feature may be a line or surface and the datum feature may be a line or a plane. In general, the tolerance zone is the area between two parallel lines or the space between two parallel planes which are parallel to the datum feature and the tolerance value is the distance between the lines or the planes. For a line parallel to a datum line, the tolerance zone may alternatively be the space within a cylinder of diameter equal to the tolerance value and whose axis is parallel to the datum. 8.11.9 Tolerances of angularity (see Table 8.16) The toleranced feature may be a line or surface and the datum feature may be a line or a plane. The tolerance zone is the area between two parallel lines or the space between two parallel planes which are inclined at the specified angle to the datum feature and the tolerance value is the distance between the lines or the planes. The tolerance zone may also be the space within a cylinder of diameter equal to the tolerance value. COPYRIGHT Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) AS 1100.101—1992 196 TABLE 8.12 TOLERANCES OF PROFILE — LINE (continued) COPYRIGHT Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) 197 TABLE 8.12 (continued) COPYRIGHT AS 1100.101—1992 AS 1100.101—1992 198 Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) TABLE 8.13 TOLERANCES OF PROFILE — SURFACE 8.11.10 Application of zero MMC Where it is necessary to specify that any errors of geometry are to be contained within the maximum material limits of a feature, this shall be indicated as shown in Figure 8.134. In this example, the indication means that if the feature is finished everywhere on its maximum limits of size, it must be perfectly square to the datum surface. Errors of squareness are permissible only if the feature is finished away from the maximum material limits of size in the direction of least material, provided that the minimum limits of size are everywhere observed. It should be noted that zero geometry tolerances can only be associated with the maximum material condition as to do otherwise would be to demand perfection. FIGURE 8.134 APPLICATION OF ZERO MMC COPYRIGHT Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) 199 COPYRIGHT AS 1100.101—1992 TABLE 8.14 TOLERANCES OF SQUARENESS (continued) Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) AS 1100.101—1992 200 TABLE 8.14 (continued) COPYRIGHT Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) 201 COPYRIGHT AS 1100.101—1992 TABLE 8.15 TOLERANCES OF PARALLELISM (continued) Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) AS 1100.101—1992 202 TABLE 8.15 (continued) COPYRIGHT Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) 203 TABLE 8.16 TOLERANCES OF ANGULARITY COPYRIGHT AS 1100.101—1992 AS 1100.101—1992 204 8.11.11 Runout (see Table 8.17) Although it conforms to the definition of ‘geometry tolerance’ in Clause 8.4.2.10, runout is in a class apart from the geometry tolerances covered in Clauses 8.10.4 and 8.11.4. In these, the geometry relationship is fundamental to the conception of the tolerance, and the method of verification is not of fundamental importance, provided that it conforms to the geometrical principle. Runout, however, is defined in terms of its measurement under rotation and demands a practical test. The resultant indication may include errors of other characteristics but without differentiating between them. The combined errors shall not exceed the stated tolerance value shown. The runout tolerance represents the maximum permissible variation of position (i.e. full indicator movement) of the considered feature with respect to a fixed point during one complete revolution about the datum axis without axial movement. Except when otherwise stated, this variation is measured in the direction indicated by the arrow at the end of the leader which points to the toleranced feature. Runout may sometimes be applied as a composite tolerance in place of separate specifications of other geometry tolerances, e.g. roundness or concentricity. But it should not, however, be used where the design requirement demands that these characteristics be separately controlled. Where required, runout tolerances as well as other geometry tolerances may be specified for a part or feature. In accordance with Clause 8.4.4.5, the width of the runout tolerance zone lies in the direction of the arrow terminating the leader. This will often, but not necessarily, be normal to the surface. Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) TABLE 8.17 TOLERANCES OF RUNOUT COPYRIGHT 205 AS 1100.101—1992 8.11.12 Total runout (see Table 8.18) The total runout tolerance represents the maximum permissible variation of the position of a point moving along a considered feature during a series of revolutions about the datum axis. The total runout tolerance applies to all measuring positions on the generated surface. Except where otherwise stated, this variation is measured in the direction indicated by the arrow at the end of the leader which points to the toleranced feature. The runout tolerance may include defects of form and defects of orientation and position from a datum axis, provided that any individual defect or the collective defects do not exceed the specified total runout tolerance across or along the total considered surface. Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) TABLE 8.18 TOLERANCES OF TOTAL RUNOUT COPYRIGHT AS 1100.101—1992 206 SECTION 9 CONVENTIONAL REPRESENTATIONS 9.1 SCOPE OF SECTION This Section specifies conventions for the representation of components and repetitive features of components. These conventions are simplified drafting techniques for depicting a component or repetitive feature, by orthographic projection, to obviate unnecessary detailing. For conventional representation peculiar to disciplines, refer to the appropriate parts of AS 1100. The conventions illustrated are typical of common items and should be amended as necessary for other items. 9.2 METHOD OF PRESENTATION A conventional representation may be either a simplified drawing of the feature being depicted or a symbol for the feature being depicted, e.g. a cross representing a rivet (see Clause 9.3.5). Where the conventional representation is a simplified drawing, it is drawn to scale. Dimensions and other details may be applied directly to this drawing or by means of tabulated data or other suitable methods. Where the conventional representation is a symbol, there is no relationship between the size of the symbol and the size of the feature it depicts. 9.3 REPRESENTATION OF FEATURES AND PARTS 9.3.1 Repeated features and parts Similar features in a regular pattern, such as holes or slots, may be represented by one or more such features in full outline and the remainder by centre-line as shown in Table 9.1. Similar parts in an assembly forming a regular pattern may be represented by one or more such part in full outline and the remainder by centre-lines. Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) TABLE 9.1 ARRAY OF SIMILAR FEATURES AND PARTS COPYRIGHT 207 AS 1100.101—1992 9.3.2 Screw threads Screw threads shall be specified in accordance with the relevant Standard. A screw thread may be represented as follows and as shown in Table 9.2: (a) End view Crests of thread are represented by a circle in a Type A line and the roots of the thread by an arc of a circle in a Type B line. The gap between the ends of the arc should subtend approximately 30° to 45°. (b) Side view — External threads and sectional internal threads Crests of thread are represented by Type A straight lines. Roots of thread are represented by Type B straight lines of length equal to the length of full thread. Runouts may also be shown, and if so as Type B lines at an angle of 30° to the axis of the thread. (c) Side view — Internal threads Crests of thread and roots of thread are represented by Type E hidden outlines (see Table 9.2 (c)). The length of the line indicating the roots of thread should equal the length of full thread. Runouts may also be shown, and if so as Type F lines at an angle of 30° to the axis of the thread. (d) Limit of useful length of threads The limit of useful length of threads is represented with a Type A line if the limit is visible or a Type F line if the limit is hidden. These lines extend across the major diameter of the thread. The representations described above apply to all types of thread form. However, if the thread is of other than V-form, a section or other detail view should be drawn to illustrate the thread form. Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) TABLE 9.2 SCREW THREADS NOTES: 1 These views are also to a ‘convention’ as the projection of a helix is not a straight line. 2 This method should be used where it is desired to show the thread runout. COPYRIGHT AS 1100.101—1992 208 9.3.3 Threaded fasteners For convenience threaded fasteners have been grouped as follows: (a) Bolts, screws, and nuts having external hexagonal features. (b) Screws having internal hexagonal features. (c) Bolts and nuts having external square features. (d) Screws having slotted or cross-recessed heads. Sizes of hexagon and square features in Items (a), (b), and (c) are related to the dimensions across opposite faces, i.e. to the nominal size of spanner or key used in assembly operations. Given the nominal size of the threaded fastener, i.e. the major diameter of the thread form, the dimensions across flats and other dimensional features shall be obtained from the relevant Standard. The features and approximate sizes of the hexagons and squares of these threaded fasteners may be represented as shown in Table 9.3 in which the proportions are based on the nominal diameter (D) * Chamfer and washer faces need not be shown, but chamfers may be represented by circular arcs as shown in Table 9.3. The slots in slotted nuts and castle nuts may be represented by lines as shown in Column 3 of Table 9.3. These lines shall be thicker than the outline. The dimensions which determine the shape and size of the various features of the circular heads of bolts and screws in Item (d) do not vary proportionately with nominal diameter (D), and hence reference should be made to the appropriate Standard to obtain values for drafting purposes. The screwdriver slot or cross-recess may be represented by lines as shown in the examples in Column 3 of Table 9.3. Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) TABLE 9.3 THREAD FASTENERS (A) EXTERNAL HEXAGONAL FEATURES (continued) * These proportions vary to some extent within the size range of threaded fasteners. COPYRIGHT Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) 209 COPYRIGHT AS 1100.101—1992 TABLE 9.3 (A) EXTERNAL HEXAGONAL FEATURES (continued) (continued) Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) AS 1100.101—1992 210 TABLE 9.3 (continued) (B) INTERNAL HEXAGONAL FEATURES COPYRIGHT Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) 211 TABLE 9.3 (continued) (D) SCREWS COPYRIGHT AS 1100.101—1992 AS 1100.101—1992 212 9.3.4 Threaded assemblies In sectional views of assembled threads, except those of thread inserts, the crest of external threads shall be represented by Type A straight lines and the roots by Type B straight lines. Thread inserts shall be shown with the external and internal crests represented by Type A straight lines and the roots by Type B straight lines. Hexagon bolt heads and nuts which are capable of being rotated should be represented across corners in both side views to show the working clearance, and for the purpose of identification. Gaps in helical-spring lock washers should be represented by lines at 45° in both side views for the purpose of identification. Screwdriver slots in machine screws should be represented with full view slots in both side views. Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) TABLE 9.4 THREADED ASSEMBLIES COPYRIGHT 213 AS 1100.101—1992 9.3.5 Riveted assemblies The complete specification of the rivets shall be given by a leader and a note. The position of a rivet is represented by the symbol + indicating the centre of the rivet in an assembly. If the assembly consists of one or more rows of rivets each containing a number of rivets, the conventional representation shown in Clause 9.3.1 may be applied as shown in Table 9.5. If the assembly consists of more than one type, diameter or length of rivet, then a set of coded symbols may be used to assist in the representation. The code may make provision for field rivets as well as shop rivets. Drawings using this method shall also contain the code or refer to a reference drawing. Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) TABLE 9.5 RIVETED ASSEMBLIES COPYRIGHT AS 1100.101—1992 214 APPENDIX A SOME COMPARISONS OF ISO STANDARDS WITH THIS STANDARD AND OTHER NATIONAL STANDARDS (Informative) A1 SYMBOLS Table A1 provides a comparison of the symbols used by ISO with those adopted by Australia, UK, USA and Canada. Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) TABLE A1 COMPARISON OF SYMBOLS (continued) COPYRIGHT 215 Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) TABLE A1 (continued) LEGEND: Same — x A = = = = same as in Column 2 (ISO) none a dimensional value an upper case letter NOTE: The symbol has been adopted by ISO/TC 10/SC 5 but not yet embodied in any ISO standard. COPYRIGHT AS 1100.101—1992 AS 1100.101—1992 216 A2 OTHER COMPARISONS A2.1 Shape of tolerance zone ISO: Zone is total width in direction of leader arrow. ∅ specified where zone is circular or cylindrical. Australia, USA and UK: Same. Canada: Zone shape evident from characteristic being controlled. Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) A2.2 Combination of position tolerancing and centre distance tolerancing ISO: Not yet defined. Australia and Canada: Specify that dimensions with centre distance tolerances shall comply with requirements independently of dimensions with geometry tolerances. USA and UK: Allow hole centres in a group to exceed centre distance tolerances by an amount equal to one-half of the specified position tolerance where the feature is at MMC. COPYRIGHT 217 AS 1100.101—1992 APPENDIX B EXAMPLES OF GEOMETRY TOLERANCE DISPLAY (Informative) Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) B1 SCOPE This Appendix illustrates a number of practical examples of the tolerance frame and tabular methods of display described in Clause 8.4.4 and compares each method on the same component. B2 EXAMPLES OF GEOMETRY TOLERANCE SPECIFICATION Figure B1 illustrates the drawing of a complicated component using the tabular method of display, whereas Figure B2 shows the same component using the tolerance frame method. Figure B3 shows a drawing of simple component also using the tolerance frame method of presentation. FIGURE B1 COMPLICATED COMPONENT — TABULAR METHOD COPYRIGHT Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) AS 1100.101—1992 218 FIGURE B3 SIMPLE COMPONENT — TOLERANCE FRAME METHOD COPYRIGHT 219 AS 1100.101—1992 APPENDIX C AXONOMETRIC PROJECTION — ADDITIONAL INFORMATION (Informative) C1 SCOPE This Appendix describes techniques for developing axonometric projections (see Clause 6.5). C2 DRAFTING AIDS The following drafting aids give assistance to drafters in the preparation of drawing in axonometric projection: (a) For isometric drawings (i) Special paper ruled in three directions at 120° to each other. (ii) Templates with a wide range of ellipses to represent circles. (b) For dimetric drawings A special type of set square illustrated in Figure C1. (c) For trimetric drawings A special type of set square illustrated in Figure C2 giving a range of angles, each with its own scale. Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) FIGURE C1 SPECIAL SET SQUARE FOR DIMETRIC PROJECTION C3 REPRESENTATION OF CIRCLES C3.1 Axonometric drawing The projection of a circle in a principal plane in any axonometric drawing is an ellipse. The major axis of this ellipse is perpendicular to the third principal axis. This relationship is of practical significance in assisting freehand drawing. (See Figure C3.) C3.2 Isometric drawing A method of construction of approximations to ellipses is illustrated in Figure C4. It should be noted that the major axis of an ellipse (e.g. part of line EG in Figure C4) in a principal plane is perpendicular to the third principal axis. C3.3 Dimetric drawing A method of construction of approximations to ellipses is illustrated in Figure C5. C4 AXONOMETRIC SCALE RATIOS C4.1 Equations Scale on OX = . . . . C4.1 (1) Scale on OY = . . . . C4.1 (2) Scale on OZ = . . . .C4.1 (3) From Equation C4.1(2), α + β < 90°. See Figure C6 for definitions of α and β. C4.2 Isometric Select α = β + 30°. Then actual scales are all equal to (2/3) , i.e. 0.816. ∴ x:y:z = 1:1:1 COPYRIGHT Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) AS 1100.101—1992 220 FIGURE C3 REPRESENTATION OF CIRCLES IN AXONOMETRIC DRAWING COPYRIGHT Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) 221 AS 1100.101—1992 1. Locate centre O by centre-lines COA and BOD. OA = OB = OC = OD = radius of circle. 2. Through B and D draw EBF and GDH parallel to COA. Through A and C draw EAH and FCG parallel to BOD. 3. Locate points J and K on GOE such that GK = EJ = OA. 4. With centre H and radius R1 (= HB) draw arc between HJ produced at L and HK produced at M. Similarly with centre F. 5. With centres J and K and radius R2 (= HB - HJ) complete the figure. FIGURE C4 CONSTRUCTION OF APPROXIMATE ELLIPSES REPRESENTING CIRCLES IN ISOMETRIC DRAWING FIGURE C5 CONSTRUCTION OF APPROXIMATE ELLIPSES REPRESENTING CIRCLES IN DIMETRIC DRAWING COPYRIGHT AS 1100.101—1992 222 C4.3 Dimetric Select α = 2β = 90°, or α = β, or 2α + β = 90° (provided α 30° and β 30°). In particular, select α = arc tan (1/63) and β = arc tan (7/9); i.e. α = 7° (approximately) and β = 41.5° (approximately) to achieve the desired x:y:z ratio. Then actual scales are (8/9), (8/9) and (2/9); i.e. 0.943, 0.943 and 0.471. ∴x:y:z = 1:1:0.5 C4.4 Trimetric Select α and β so that α + 2β 90°, or 2α + β 90°, or α β. Using a special set square, such as that shown in Figure C2, scale ratios will depend on the angles involved. For example, if provision is made for α = 10° and β = 45° then the actual scales are 0.936, 0.908 and 0.548. ∴x:y:z = 1:0.970:0.585. Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) FIGURE C6 AXONOMETRIC SCALE RATIOS COPYRIGHT 223 AS 1100.101—1992 APPENDIX D OBLIQUE PROJECTION — ANGLE OF LINE OF SIGHT (Informative) Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) D1 SCOPE This Appendix demonstrates the relationship between the angle of the line of sight and the scale on the receding axis in oblique projected views. D2 CALCULATION OF SCALE Let OP be the third principal axis of an object of length a, where O is in the picture of the plane and P is behind the picture plane. (See Figure D1). FIGURE D1 CALCULATION OF SCALE Let Θ be the angle that the parallel lines of sight make with the picture plane. Then a line of sight from the point P will lie on the surface of a cone, the base of which is in the picture plane and the radius of which is r, where r = a cot Θ. Any radial line of this circle represents the projection of OP and hence, the scale of the oblique projection of OP to the true length of OP is cot Θ. COPYRIGHT AS 1100.101—1992 224 Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) Any plane through the axis of this cone may then be selected and will make an angle β, say, with the horizontal and the intersection of this plane on the picture plane will produce an oblique projection of OP. Thus although the scale is fixed by cot Θ, β may be any angle in the oblique drawing. As noted in Clause 6.6.2, this is, for convenience, selected as 30°, 45°, or 60°. To obtain equal scale on receding axis, i.e. ‘cavalier’: Θ = arc cot 1 = 45° To obtain a scale ratio of 0.5 on receding axis, i.e. ‘cabinet’: Θ = arc cot 0.5 = 63° 26’ approx. To obtain any other scale ratio (R) on receding axis, i.e. ‘general oblique’: Θ = arc cot R COPYRIGHT 225 AS 1100.101—1992 APPENDIX E MAXIMUM MATERIAL PRINCIPLE (Informative) E1 SCOPE This Appendix provides an example of specifying geometric tolerance applied on a maximum material condition basis. E2 INTRODUCTION The maximum material principle arises from consideration of the free assembly of two mating groups of features and is a result of the development of the theory of tolerancing for position, concentricity and symmetry. This theory of tolerancing establishes for each functional group — (a) a geometric reference frame (GRF); (b) a tolerance diagram; and (c) a virtual component. Assembly is assured if the virtual components are capable of assembly. The example given in Figure E1 illustrates the above theory. NOTE: The virtual size of a hole is its low size minus the position tolerance. The virtual size of a pin is its high size plus the position tolerance. The virtual sizes for the mating groups are determined as follows: 4 x ∅ 8 holes : ∅ 8 - ∅ 0.2 = ∅ 7.8 ∅ 10 hole C: ∅ 10 - ∅ 0 = ∅ 10 4 x ∅ 7.5 pins : ∅ 7.5 + ∅ 0.2 = ∅ 7.7 ∅ 10 pin D : ∅ 10 + ∅ 0 = ∅ 10 Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) Study of the two diagrams will show that the two virtual components are capable of assembly and hence the tolerances indicated will ensure assembly. E3 CONDITIONS FOR FREE ASSEMBLY OF COMPONENTS It should be noted that more clearance for assembly will be present if the actual sizes of the mating features are away from the maximum material limits of size, and if the actual errors of form or position are less than the maximum. It follows, therefore, that if this is the case, the error of form or position may exceed the specified tolerance without preventing assembly. This effective increase of tolerance, which is applicable to toleranced centre distances (see Clause 8.3.11) as well as to tolerances of position and to certain tolerances of form, is advantageous for manufacture, but may not always be permissible from the functional point of view. For example, in position tolerancing the increase of tolerance can generally be permitted on the centre distances of such features as bolt holes and studs, but it may not be permissible in such things as kinematic linkages and gear centres. COPYRIGHT Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) AS 1100.101—1992 226 (b) Geometric reference frame for group 1 FIGURE E1 (in part) MAXIMUM MATERIAL PRINCIPLE RELATED TO MATING COMPONENTS COPYRIGHT Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) 227 AS 1100.101—1992 FIGURE E1 (in part) MAXIMUM MATERIAL PRINCIPLE RELATED TO MATING COMPONENTS COPYRIGHT AS 1100.101—1992 228 APPENDIX F ORIENTATION OF ACTUAL LINES AND SURFACES (Informative) F1 SCOPE This Appendix provides an illustration of the definition of the angle between two lines, as described in Clause 8.3.8.2. F2 DEFINITION The orientation of an actual line is the orientation of a pair of parallel straight lines with the least separation which completely envelop the actual line. The orientation of an actual surface is the orientation of a pair of parallel planes with the least separation which completely envelop the actual surface. Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) F3 EXAMPLE Some possible orientations of the ideal line or surface relative to the actual line or surface are illustrated in Figure F1 such as A1—B1, A2—B2 and A3—B3. FIGURE F1 ORIENTATION OF IDEAL LINE OR SURFACE RELATIVE TO THE ACTUAL LINE OR SURFACE Orientation A1—B1 A2—B2 A3—B3 Corresponding separation of enveloping lines h1 h2 h3 or planes In Figure F1 h1<h2<h3 Hence, the orientation of the ideal line or surface corresponding to the actual lines or surfaces is A 1—B1. COPYRIGHT 229 AS 1100.101—1992 APPENDIX G COMPARISON OF COORDINATE AND POSITION TOLERANCING (Informative) Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) G1 SCOPE This Appendix provides reasons for using positional tolerances when there are more than two features in a functional group. G2 COMPARISON OF COORDINATE TOLERANCES WITH POSITION TOLERANCES IN THE CONTROL OF ERRORS IN POSITION OF RELATED FEATURES Where there are only two features to be correlated, either the method of directly toleranced coordinate dimensions or that using position tolerances may be suitable, but where the group of features contains more than two features, the latter method offers definite advantages. Figure G1 shows a component with four holes toleranced by the directly toleranced coordinate dimension method. The requirement could be interpreted as being that of a series of groups of two features, i.e. AB, BC, and CD. If this interpretation be acceptable, there is no harm in using this method of tolerancing but if the four holes constitute one group which has to accept four pins on another component, the inevitable accumulation of tolerances on dimensions AC, BD, and AD may lead to difficulty in assembly. It would then be necessary to reduce the tolerances on AB, BC, and CD to one-third of that theoretically permissible in order to keep the variations of AD within acceptable limits. Even if the dimensioning in Figure G2 were used, there is a possibility of an accumulation of errors on dimensions BC, CD, and BD which will require the tolerance on AB, AC, AD to be restricted to one-half of that which is theoretically permissible. The holes shown in both Figures G1 and G2 would also need to be controlled in the direction at right angles to the horizontal centre-line. FIGURE G1 COORDINATE TOLERANCE METHOD FIGURE G2 POSITION TOLERANCE METHOD G3 COORDINATE TOLERANCING Where features are positioned in relation to prepared plane surfaces as in Figure G3, the accuracy of their positioning depends largely on the mutual accuracy of the plane surfaces. Such a system of holes is in reality not a single group but a number of simple groups of two features of which one is a plane surface and the other a hole. The tolerances of position can be shown graphically as in Figure G4. This is not strictly correct (see Figure 8.56). If it is assumed that the plane surfaces are exactly at 90° to each other, the maximum permissible variation in centre distances AD and BC is 2 x 0.4 = 0.5656. If this component is to assemble with another having four pins, this value of 0.5656 should be used when assessing the amount of clearance necessary to ensure the assembly of the mating features. If, however there is no guarantee of accuracy between the plane surfaces, the normal positions of the holes may not lie at the corners of a true square and it will then be impossible to forecast whether or not there will be trouble-free assembly. The relative positions of holes dimensioned as in Figure G5 are even more difficult to control than those in Figures G1, G2, and G3 since each of the four centre distances can be correct even when the framework of the centre-lines departs considerably from the true rectangular shape. COPYRIGHT AS 1100.101—1992 230 Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) G4 POSITION TOLERANCING WITH TRUE POSITION DIMENSIONS The use of position tolerances avoids all the difficulties discussed in Paragraphs G2 and G3. The difficulties are avoided because the position tolerance for a feature limits the variation of position in a defined group of features, and not the variation of specified centre distances. In Figure G6, the drawing and the tolerance diagram illustrate that there is no accumulation of errors of position and that the permissible variation of centre distances, even diagonally, is the same between any pair of holes. This considerably simplifies the assessment of the sizes of mating features to maintain required clearances. G5 RECTANGULAR TOLERANCE ZONES In the exceptional case of tolerance zones other than circular being essential (e.g. square or rectangular), they may be specified relative to the true geometric position defined by basic dimensions as shown in Figure G7. However this practice is not recommended. G6 RECOMMENDATION Positional tolerances should be applied wherever there are more than two features in a functional group, and the maximum material condition concept specified wherever functionally possible, to facilitate production and checking. FIGURE G6 USE OF POSITION TOLERANCES COPYRIGHT 231 AS 1100.101—1992 Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) FIGURE G7 TOLERANCE ZONES SPECIFIED RELATIVE TO TRUE GEOMETRIC POSITION COPYRIGHT AS 1100.101—1992 232 APPENDIX H INTERPRETATION OF DATUMS (Normative) Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) H1 SCOPE This Appendix sets out methods for establishing datums for a number of applications. H2 INTRODUCTION Features indicated as datums have inherent inaccuracies resulting from the production process. These may take the form of convex, concave or conical deviations. The following methods are examples for establishing datums. H3 DATUM BEING A STRAIGHT LINE OR A PLANE The datum feature shall be arranged in such a way that the maximum distance between it and the simulated datum feature has the least possible value. Should the datum feature not be stable with the contacting surface, suitable supports should be placed between them at a practical distance apart. For lines, use two supports (see Figure H1) and for flat surfaces, use three supports. FIGURE H1 CONTACT BETWEEN DATUM FEATURE AND SIMULATED DATUM FEATURE H4 DATUM BEING THE AXIS OF A CYLINDER The datum is the axis of the largest inscribed cylinder of a hole or the smallest circumscribed cylinder of a shaft, so located that any possible movement of the cylinder in any direction is equalized (see Figure H2). FIGURE H2 DATUM IS AXIS OF A CYLINDER COPYRIGHT 233 AS 1100.101—1992 H5 DATUM BEING THE COMMON AXIS OR COMMON MEDIAN PLANE In the example shown in Figure H3, the datum is the common axis formed by the two smallest circumscribed coaxial cylinders. Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) FIGURE H3 DATUM IS COMMON AXIS OR COMMON MEDIUM PLANE H6 DATUM BEING THE AXIS OF A CYLINDER AND PERPENDICULAR TO A PLANE In the example shown in Figure H4 the datum ‘A’ is the plane represented by the contacting flat surface and the datum ‘B’ is the axis of the largest inscribed cylinder, perpendicular to the datum ‘A’. NOTE: In the above example, the datum ‘A’ is considered to be primary and the datum ‘B’ secondary. FIGURE H4 DATUM IS AXIS OF A CYLINDER AND PERPENDICULAR TO A PLANE COPYRIGHT Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) AS 1100.101—1992 234 NOTES COPYRIGHT 235 AS 1100.101—1992 Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) INDEX Abbreviations Gener al Decod ing Encod ing Aligned sections Angle be tween two lines Angular dimens ions Tolerancing Angular surfaces — Tolerancing Application of lines Arrange ment drawing Arrowhe ads Assembly Assembly drawing Auxiliary aligned section Auxiliary dimens ions Auxiliary planes of projection Auxiliary views Axis (of a feature) Axonome tric projection Axonome tric sca le ratios Clause 1.4 Tab le 1.2 Tab le 1.1 Clause 7.4.5 Append ix F Clause 8.2.4.3 Clause 8.3.8.2, Appendix F Clause 8.3.12 Clause 3.5 Clause 2.2.2 Clause 4.3.3, 4.3.4.4. Clause 2.2.15 Clause 2.2.3, 2.5.8.3 Clause 7.4.5 Clause 8.2.5.4 Clause 6.4.5 Clause 6.3.7 Clause 8.3.2.1 Clause 6.5, Appendix C Clause C4 Basic dimension Basic dimension symb ol Basic tape r (or basic ang le) metho d Bolts — Conventional represen tation Borders Break lines in sections Clause 8.3.2.2 Clause 8.3.3.6 Clause 8.3.13.1(a), 8.3.13.2 Clause 9.3.3, Tabl e 9.3 Clause 2.5.1 Clause 7.4.9.5 Cabinet projection Camera alignment marks Cavalier projection Characters Decimal Height Spacing Thickness Use of Vulgar fractions Circles Dimensioning Repre sentation in projections Control drawing Conventional represen tations Clause Clause Clause Clause Clause Clause Clause Clause Clause Clause Coordinate system in spatial geome try Countersinks, coun terboxes , spotfaces — Dimens ioning Curve Dimensioning Tolerancing Cutting planes Cutting planes — Sections Dashes Datum Dimension Featu re Group Ident ifying letters Reference frame Simulated Specification and interpretation System Targe t Targe t symbol Decimal form Descriptive geome try Detail asse mbly drawing Detail drawing Diagrammatic drawing Diameters — Dimens ioning Dimension Dimension datum symb ol Dimension limits Dimension lines 6.6.2 2.5.3 6.6.2 4.1.1. 4.1.6 4.1.2 4.1.4 4.1.3 4.1.5 4.1.7 Clause 8.2.6.1, 8.2.6.2 Clause C3 clause 2.2.4 Section 9, See also AS 1100. 201 Clause 6.4.2 Clause 8.2.6.8 Clause Clause Clause Clause 8.2.6.6, 8.2.6.11 8.3.15 6.4.6 7.2 Clause 3.2.2 Clause 8.3.2.3, 8.6.2, 8.6.5, Appendix H Clause 8.3.2.4 Clause 8.3.2.5, 8.3.3.3, 8.6.4 Clause 8.4.2.1, 8.6.5 Clause 8.3.3.4 Clause 8.6.3 Clause 8.3.2.6 Clause 8.6 Clause 8.4.2.2 Clause 8.3.2.7, 8.6.6 Clause 8.3.3.5 Clause 4.1.6 Clause 6.4.1 Clause 2.2.5 Clause 2.2.6, 2.5.8.2 Clause 2.2.7 Clause 8.2.6.1 Clause 8.1.1.1, 8.2.4 Clause 8.3.3.9 Clause 8.3.9, 8.3.11.2 Clause 3.5.2(b), 8.2.3.2 Dimensioning Angular dimens ions Arrangeme nt Auxiliary dimens ion Chamfers Count ersinks, coun terbores , spo tfaces Curve d surfaces Diameters Dimension lines Dimensions Equal dimens ions Functional dimensions Holes Leade rs Linear dimens ions Not-to-scale dimensions Projection lines Pictorial drawings Profiles Radii Reference dimens ion Screw threads Slopes Spher ical diameter Squar es Symbo ls Tabular presen tation of dimensions Taper s Dimensions of lines Dimetric projection Dots Terminating line Terminating leaders Used as dec imal sign Drawing Drawing sheet s Layou t Materials Sizes Drawing types Arrangeme nt Assem bly Control Detail asse mbly Detail Diagramma tic Electrotechno logy Gener al arrange ment Installation Monod etail Multideta il Subas semb ly Tabulated Works as exec uted Clause Clause Clause Clause Clause 8.2, 8.3 8.2.4.3 8.2.5 8.2.5.4 8.2.6.7 Clause 8.2.6.8 Clause 8.2.6.6, 8.2.6.11 Clause 8.2.6.1 Clause 8.2.3.2 Clause 8.2.4 Clause 8.2.6.5 Clause 8.2.2.1 Clause 8.2.6.4 Clause 8.2.3.3 Clause 8.2.4.2 Clause 8.2.5.3 Clause 8.2.3.1 Clause 6.8.5 Clause 8.2.6.11 Clause 8.2.6.2 Clause 8.2.5.4.2 Clause 8.2.6.9 Clause 8.2.6.12 Clause 8.2.6.1(e) Clause 8.2.6.3 Figure 4,14, Clause 8.2.1 Clause 8.2.5.2 Clause 8.2.6.10, 8.2.6.12 , Tab le 8.1 Clause 3.2 Clause 6.5.2, 6.5.3.2,6.5.4.2 Clause 4.3.4.4 Clause 4.3.4.1 Clause 4.3.4.2 Clause 4.1.6.1 Clause 2.2.1 Clause 2.5 Clause 2.3 Clause 2.4 Clause Clause Clause Clause Clause Clause Clause Clause Clause Clause Clause Clause Clause Clause 2.2.2 2.2.3 2.2.4 2.2.5 2.2.6 2.2.7 2.2.13 2.2.8 2.2.9 2.2.10 2.2.11 2.2.15 2.2.12 2.2.14 Electrotechnology drawing End produc t Engineering and arch itectural drawing sca les Envelope principle Envelope symb ol Equal dimens ions Clause 2.2.13 Clause 2.2.16 Clause Clause Clause Clause 5.4.1, Tabl e 5.1 8.3.5, 8.3.10 8.3.3.10 8.2.6.5 Fas tening elements in sections Fea ture Fea ture symbols Filing margin First ang le projection — Symbol First ang le projection Fitting to gaug e or mating part Flat surfaces Flow cha rt Fold lines Form tolerance s Format lines Full sections Fun ctional dimensions Clause Clause Clause Clause Clause Clause Clause Clause Clause Clause Clause Clause Clause Clause 7.4.9.1 8.3.2.8, 8.3.11 8.3.3.3, 8.3.3.6 2.5.1.2 2.5.6(a) 6.3.2, 6.3.3 8.3.13.1(c) 3.6.1 2.2.17 2.5.7 8.11.4 2.5.12 7.4.2 8.2.2.1 COPYRIGHT AS 1100.101—1992 Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) Gauge or mating pa rt Gears and splines — Orientation and location General arrange ment drawing General oblique projection Geometric reference frame Geometry tolerancing — See also Tolerancing Angularity Circularity (roundne ss) Conce ntric featu res Conce ntricity Coord inate and pos ition toleran cing Count erbo red holes Cylindricity Datum specification Examp les Featu re pa tterns Flatness Form Line Maximum material condition Metho ds — Preferen ces MMC 236 Clause 8.3.13.4 Clause Clause Clause Clause 8.9 2.2.8 6.6.2 8.4.2.3 Clause Clause Clause Clause Clause 8.4 8.11.9 8.11.4.4 8.10.11 8.10.4 MMC — Zero Non-c ircular features Orientation Parallelism Position Profiles Projected tolerance zone Runou t Runou t — Tota l Slots Spher ical features Squar enes s Straightn ess Surface Symmetry Tabular method Tolerance frame method Total runout True po sition dimension Virtual cond ition Zero MMC Grid referencing Appendix G Clause 8.10.11 Clause 8.11.4.5 Clause 8.6 See AS1100.20 1 Clause 8.10.9 Clause 8.11.4.3 Clause 8.11.4 Clause 8.11.5 Clause 8.5 Clause 8.4.4.2 Clause 8.10.6, 8.10 .7, 8.10.8 Clause 8.11.10 Clause 8.10.12 Clause 8.11.6 Clause 8.11.8 Clause 8.10, G4 Clause 8.11.5 Clause 8.10.10 Clause 8.11.11 Clause 8.11.12 Clause 8.10.12 Clause 8.10.13 Clause 8.11.7 Clause 8.11.4.2 Clause 8.11.5 Clause 8.10.5 Clause 8.4.5, Appendix B Clause 8.4.4.3, Appendix B Clause 8.11.12 Clause 8.10.3 Clause 8.7 Clause 8.11.10 Clause 2.5.4 Half sections Hatching Height of cha racters Holes — Dimensioning Holes in flanges in sec tions Clause Clause Clause Clause Clause 7.4.3 7.3 4.1.2 8.2.6.4 7.4.9.3 Installation Installation drawing Interpo sed sections Isometric projection Clause Clause Clause Clause 6.5.4.1 Clause Clause Clause 2.2.18 2.2.9 7.4.7 6.5.2, 6.5.3.2, Item Reference nu mber Reference s Lay out of drawings she ets Lea ders Lea st material cond ition Letters Line density Line spacing Lines Adjacent parts Applications Break lines Centre-lines Centre-lines — Short Centroidal Cutting planes Dashe s Density Dimension Dimension of lines Fictitious outline Flat surface Fold lines 4.2.2.1 4.2.2.2 4.2 Clause 2.5, 2.5.8 Clause 8.2.3.3 Clause 8.4.2.4 See Chara cters Clause 3.4 Clause 3.3 Clause Clause Clause Clause Clause Clause Clause Clause Clause Clause Clause Clause Clause Clause 3.5.9(a) 3.5 3.5.3 3.5.6 3.5.2(h) 3.5.9(c) 3.5.7 3.2.2 3.4 3.5.2(b) 3.2 3.5.2(a) 3.6.1 3.5.2(g) Format Hatching Hidden ou tline Imaginary interse ctions Material to be removed Movab le pa rts Outlines Part views and sec tions Pitch lines Priority Projection Rectangular op ening Revolved section Spacing Special requirements Symmetry Types Linear dimens ions Linear dimens ions — Tolerancing Loc al or pa rt sections Clause Clause Clause Clause Clause Clause Clause Clause Clause Clause Clause Clause Clause Clause Clause Clause Clause Clause Clause Clause 2.5.12 3.5.2(c) 3.5.4 3.5.2(f) 3.5.6 3.5.9(b) 3.5.1 3.5.3 3.5.6 3.7 3.5.2(b) 3.6.2 3.6.3 3.3 3.5.8 3.6.3 3.1, 3.5 8.2.4.2 8.3.8.1 7.4.4 Material or parts list Materials Maximum material con dition symbol Maximum material principle Symbo l Maximum material size Mon odet ail drawing Multidetail drawing Clause Clause Clause Clause Clause Clause Clause Clause 2.5.11 2.3 8.3.3.7 8.3.6, Appendix E 8.3.3.7 8.3.2.16 2.2.10 2.2.11, 2.5.8.3 Non-preferred sizes Not-to-scale dimensions Notes Gener al Local Supplemen t to symbo ls Tolerance Notes on drawings Numerals Nuts — Conventional represe ntation Clause 2.4.2 Clause 8.2.5.3 Clause 8.2.7(a) Clause 8.2.7(b) Clause 4.3.4.8 Clause 8.3.8.3 Clause 8.2.7 See Chara cters Clause 9.3.3, Tabl e 9.3 Oblique projection Order of priority of coincident lines Orienta tion of drawings Orthogo nal projection Clause Clause Clause Clause Part Part numb er Partial views Parts list Perspec tive projection Pictorial drawings Pipelines Plane faces — Represen tation Planes — Sections Planes — Spatial geom etry Auxiliary Cutting Inclined Principal Notation Trace Clause 2.2.19 Clause 2.2.20 Clause 6.3.6 Clause 2.5.11 Clause 6.7 Clause 6.8 See AS1100.20 1 Clause 3.6.1 Clause 7.2 Planes of projection Preferred sizes Principal planes Principle of indep ende ncy Print trimming line Profile — Dimensioning Profile and curved surfaces — Tole ranc ing Projected tolerance zon e symbo l Projection Axono metric Cabinet Cavalier Dimetric Gener al oblique Ident ification Indication Isome tric Oblique COPYRIGHT 6.6, Appendix D 3.7 2.5.14 6.3 Clause 6.4.5 Clause 6.4.6 Figure 6.19 Clause 6.4.3 Clause 6.4.4 Clause 6.4.5, Figu re 6.19 , Figure 6.20 Clause 6.4.5 Clause 2.4.1 Clause 6.4.3 Clause 8.3.4 Clause 2.5.2 Clause 8.2.6.11 Clause 8.3.15 Clause 8.3.3.8 Clause 6.5, 6.5.1, Appendix C Clause 6.6.2 Clause 6.6.2 Clause 6.5.2, 6.5.3, 6.5.4.2 Clause 6.6.2 Clause 6.1 Clause 2.5.6 Clause 6.5.2, 6.5.3, 6.5.4.1 Clause 6.6, 6.6.1 237 Orthogona l Auxiliary views Deviation from method First ang le Partial views Removed views Repetitive features Rounded and filleted intersections Selection of views Symmetrical pa rts Third ang le Persp ective Trimetric Types Projection lines Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) Radii Dimensioning Tolerancing Rectang ular op ening Removed sec tions Removed views Repeate d featu res and pa rts — Conventional repres enta tion Repetitive features Revolved sections Riveted assemb lies — Conve ntional repre sentation Roll drawings Rounded and filleted interse ctions Scales Indication Recom mend ed ratios Screw threads Conve ntional represen tation Orientation and location Pictorial drawings Screws — Conven tional repre sentation Sectioning Sections Conve ntions Views Sheet de signation Size Actual Least material Limits of Local Mating Maximum material Nominal Size of drawing sheet s Slashes Slots Spacing of cha racters, words and lines Spatial geo metry Spheres — Dimensioning Squares — Dimensioning Surveying and map ping scales Symbol Symbols Compa risons Depth Diameter Dimensioning Hole Notes Radius Slope Taper Tolerancing Tolerancing, geom etry Clause Clause Clause Clause Clause Clause Clause 6.3, 6.3.1 6.3.7 6.3.5 6.3.2, 6.3.3 6.3.6 6.3.8 6.3.11 Clause Clause Clause Clause Clause Clause 6.5.4.3 Clause Clause 6.3.9 6.3.4 6.3.10 6.3.2, 6.3.3 6.7, 6.7.1 6.5.2, 6.5.3, 6.2 3.5.2(b), 8.2.3.1 Clause Clause Clause Clause Clause 8.2.6.2 8.3.15 3.6.2 7.4.8 6.3.8 Clause 9.3.1 Clause 6.3.11 Clause 3.6.3, 7.4.6 Clause 9.3.5 Clause 2.4.3, 2.5.1.3 Clause 6.3.9 Section 5 Clause 5.3 Clause 5.4 Clause 9.3.2 Clause 8.8 Clause 6.8.4 Clause 9.3.3, Tabl e 9.3 Section 7 Clause Clause Clause Clause Clause Clause Clause Clause Clause Clause Clause Clause Clause Clause 7.4.9 7.4 2.5.5 8.3.2.10 8.3.2.11 8.3.2.12 8.3.2.13 8.3.2.14 8.3.2.15 8.3.2.16 8.3.2.17 2.4 4.3.4.5 8.10.12 Clause 4.1.4 Clause 6.4 Clause 8.2.6.1(e) Clause 8.2.6.3 Clause 5.4.2, Tabl e 5.2 Clause 4.3.2.1 Clause 4.3 Appendix A Clause 8.2.6.4(b), Tab le 8.1, Figure 4.14 Clause 8.2.6.1(a), Tab le 8.1, Figure 4.14 Tab le 8.1, Figure 4.14 Clause 8.2.6.4(a), Tab le 8.1, Figure 4.14 Clause 4.3.4.8 Clause 8.2.6.2(a), Tab le 8.1, Figure 4.14 Clause 8.2.6.12, Figure 4.14 Clause 8.2.6.12, Figure 4.14 Clause 8.3.3, Figu re 4.14 Clause 8.4.3, Tabl e 8.2, Figure 4.14 AS 1100.101—1992 Square Clause 8.2.6.3, Tab le 8.1, Figure 4.14 Clause 8.3.3.10, 8.3.5 Clause 8.3.3.7, 8.3.6, 8.4.5.8 Clause 8.3.3.8 Symmetrical ob jects Symmetrical pa rts System Tab ular method Tab ular presen tation of dimensions Tab ulated drawing Tap ers Dimensioning Tolerancing Terminator Thickne ss of chara cter lines Third ang le projection Symbo l Threade d assem blies— Conve ntional represen tation Threade d fasteners — Conve ntional represen tation Threads — Dimensioning Three toleranced dimens ions method Title block Toleran ce Bilateral Diagram Form Frame method Geome try Indication metho ds Orientation Position Profile Runou t Unilateral Zone Toleran ced tape r (or angle) metho d Toleran ces of drawing sheets Toleran ces of pos ition Toleran cing ( see also Geome try toleran cing) Angle be tween two lines Angular dimens ions Clause Clause Clause Clause 8.3.3.3 3.6.3 6.3.10 2.2.21 Clause 8.4.5 Clause 8.2.5.2 Clause 2.2.12 Clause Clause Clause Clause Clause Clause 8.2.6.10, 8.2.6.12 8.3.13 4.3.2.2 4.1.3 6.3.2, 6.3.3 2.5.6(a) Clause 9.3.4 Clause 9.3.3 Clause 8.2.6.9 Clause 8.3.13.5 Clause 2.5.9, Figures 2.6-2.9 Clause 8.1.1.2 Clause 8.3.2.19 Clause 8.4.2.8 Clause 8.4.2.9 Clause 8.4.4.3 Clause 8.4.2.10 Clause 8.3.7 Clause 8.11 Clause 8.4.2.11 Clause 8.11 Clause 8.11 Clause 8.3.2.20 Clause 8.3.2.2 Clause 8.3.13.3 Clause 2.4.4, Clause 8.10 Typ es of lines Clause 8.3 Appendix F Clause 8.3.8.2, Appendix F Clause 8.3.12 Clause G3 Clause 8.3.8 Clause 8.3.10 Clause 8.3.11 See Geome try toleran cing Clause 8.3.9 Clause 8.3.8.1, 8.3.9.3 Clause 8.3.8.3 Clause G4 Clause 8.3.15 Clause 8.3.14 Figure 4.14, Clause 8.3.3 Clause 8.3.13 Clause 6.4.5 Clause 6.5.2, 6.5.3.2, 6.5.4.3 Clause 3.1 Views Designation Selection Virtual cond ition Virtual size Vulgar fractions Clause 6.1.1 Figure 6.1 Clause 6.3.4 Clause 8.4.2.6, 8.7 Clause 8.4.2.7 Clause 4.1.7 Web s, ribs, spok es in sections Works as executed drawing Clause 7.4.9.2 Clause 2.2.14 Angular surfaces Coord inate Direct methods Envelope principle Featu res Geome try Limits of dimensions Linear dimens ions Notes Position Profile and curved surfaces Radii Symbo ls Taper s Traces of planes Trimetric projection COPYRIGHT Accessed by RMIT UNIVERSITY LIBRARY on 29 Jul 2013 (Document currency not guaranteed when printed) This page has been left intentionally blank.