AMERICAN
NATIONAL
STANDARD
Square and Hex Nuts
-~
~~~
ANSI B18.2.2 - 1972
(REVISION OF B18.2.2
- 1965)
SECRETARIA T
SOC1 E T Y OF AUTOMOTIVE ENGINEERS
THE AMERICAN SOCIETY OF MECHANICAL ENGINEERS
PUBLISHED BY
THE
A M E R I C A N
S O C I E T Y
United Engineering Center
OF M E C H A N I C A L E N G I N E E R S
3 4 5 E a s t 4 7 t h Street
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T H E AMERICAN SOCIETY O F MECHANICAL ENGINEERS
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A n y part of this standard may b e quoted. Credit lines should read: “Extracted from American
National Standard, Square and Hex Nuts, ANSI B18.2.2-1972, with the permission of the publisher,
T h e American Society of Mechanical Engineers, United El‘gineering Center, 345 E a s t 47th Street,
New York, N . Y . 10017.
9009275 0037042 978
FOREWORD
American National Standards Committee B I 8 for the standardization of bolts, screws, nuts, rivets and
similar fasteners was organized in March 1922, as Sectional Committee B I 8 under the aegis of the American
Engineering Standards Committee (later the American Standards Association, then the United States of
America Standards Institute and, as of October 6, 1969, the American National Standards Institute, Inc.),
with the Society of Automotive Engineers and the American Society of Mechanical Engineers as joint
sponsors. Subcommittee 2 was subsequently established and charged with the responsibility for technical
content of standards covering wrench head bolts and nuts.
Subcommittee 2, after appraisal of the requirements of industry, developed a proposed standard series of
bolt head and nut dimensions. This proposal was finally approved and designated a Tentative American
Standard in February 1927.
Following reorganization of the B I 8 Committee in 1947, Subcommittee 2 was asked to expand the
standard on head proportions into a complete product standard. A proposal covering square and hexagon
head bolts, and nuts, hexagon head cap screws and automotive hexagon head bolts was prepared and submitted to the B18 Committee in April 1950. While this draft was under consideration, the B I 8 Committee
received a proposal from the British Standards Institution for unification of dimensions on products incorporating Unified screw threads. The Committee welcomed the opportunity of discussing the proposals
and an American-British-CanadianConference was held in New York, June 1-2, 1950.
I t was agreed in the Conference that the essentials of unification could be accomplished by selection of
mutually satisfactory across-the-flatsdimensions, since this would permit the use of the same wrenches and
because other features would rarely affect interchangeability. After due consideration, suitable existing
across-the-flatsdimensions were selected for the hexagon products affected.
In i t s meeting of October 13, 1950, Subcommittee 2 agreed to incorporate in the proposed standard the
conference recommendations on 1/4 in. hexagon head bolts, 5/8 in. hexagon head cap screws and automotive
hexagon head bolts, 5/16 and 3/8 in. regular hexagon and square nuts, and 7/16 in. light and regular hexagon
and square nuts. At a subsequent meeting of Subcommittee 2, further changes were adopted in order to combine the light and regular series of nuts and to combine the automotive hexagon head bolt, hexagon head cap
screw, and regular hexagon head close tolerance bolt.
In view of the progress made in the United States and the urgency of standardization for mutual defense,
the British Standards Institution sponsored a second Conference in London in April 1951 to complete the
unification of certain hexagon bolts and nuts.
At a meeting on June 8, 1951, Subcommittee 2 reaffirmed i t s acceptance of the unified dimensions which
corresponded with those in the March 1951 draft, but attempted to select better nomenclature for the unified
products. A final draft incorporating the nomenclature "Finished Hexagon Bolts and Nuts" and containing
numerous editorial changes was submitted for letter ballot in September 1951. Following approval by the
E18 Committee and the sponsors the proposal was presented to the American Staddards Association for approval and designation as an American Standard. This was granted on March 24, 1952.
It being recognized the standard was in need of additional refinements, Subcommittee 2 began work immediately to eliminate these shortcomings. A proposed revision removing inconsistencies with respect to
fillets, improving the length tolerances on heavy hexagon bolts and incorporating numerous other corrections
and clarifications of an editorial nature, resulted. The most noteworthy editorial change was a decision to
combine the coverage for hexagon cap screws and square head set screws from the B18.2 standard with the
coverage for slotted head cap screws and slotted headless set screws from the B18.6 standard for publication
in a separate document. The requirements for the unified hexagon cap screws and finished hexagon bolts
being identical in the overlapping sizes, this data would now be available in two publications. Following ap...
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A first revision of the document was designated as an American Standard in March, 1933 and was followed
by a second revision which was granted approval as an American Standard in January 1941.
7009275 0037043 ô04
provals by the B18 Committee and sponsor organizations, the proposal was submitted to the American
Standards Association and declared an American Standard on February 2, 1955.
At a meeting in February 1960, Subcommittee 2 approved a recommendation to reduce the head heights
for heavy, heavy semi-finished and heavy finished hexagon bolts which was subsequently approved by letter
ballot of the B18 Committee on August 16, 1960. A proposed standard for heavy hexagon structural bolts
submitted and accepted by Subcommittee 2 a t i t s October 17, 1960 meeting was approved by letter ballot
of the 818 Committee on May 9, 1961. To meet the urgent needs of the steel construction industry it was
considered necessary to publish the standard for the structural bolts immediately. Consequently, Appendix
IV to ASA B18.2-1960 containing coverage for the revised heavy hexagon bolts and the new heavy hexagon
structural bolts, was released in 1962.
In October of 1961, subcommittee 2 appointed a subgroup to review all product standards for square and
hexagon bolts, screws and nuts, and to recommend simplifications which would be compatible with technical,
production and distribution advances that had occurred over the prior several years. The sub-group presented
its recommendations a t a meeting of Subcommittee 2 in October of 1962. It being agreed that the internally
and externally threaded products should be published in separate documents as suggested, draft proposals for
each were completed.
The proposed revision for square and hex nuts incorporated the following subgroup recommendations:
discontinuation of regular semi-finished nuts; elimination of regular hexagon and heavy hexagon nuts in
sizes 1/4 through 1 in.; elimination of finished hexagon nuts in sizes larger than 1-1/2 in.; elimination of the
washer face semi-finished style on finished series nuts in sizes E/8 in. and smaller and heavy series nuts in
sizes 7/16 in. and smaller; removal of machine screw nuts (these nuts now contained in B18.6.3); and adoption of an abbreviated product nomenclature. Letter ballot of this proposal to the B18 Committee resulted in
approval. Following acceptance by the sponsor organizations the revision was submitted to the American
Standards Association and designated American Standard ASA B18.2.2 on September 8, 1965.
Subcommittee 2 continued to further develop refinements initiated by the simplification subgroup and
study changes suggested by consumer interests. This work culminated in Subcommittee acceptance of a 1970
proposal incorporating, in addition to numerous editorial changes, revisions to the requirements on angularity
of bearing face and countersink diameters for the various hex nuts and heavy hex nuts, and inclusion of an
appendix covering the gaging of slots in slotted nuts. The proposed revision, after approval by letter ballot of
the B18 Committee in March 1970, was subsequently approved by the sponsors and submitted to the
American National Standards Institute for designation as an American National Standard. This was granted
on January 18, 1972.
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A revision of this document comprised of numerous editorial corrections and inclusion of an appendix for
grade markings was duly approved and designated an American Standard on April 18, 1960.
AMERICAN NATIONAL STANDARDS COMMITTEE 6 1 8
Standardization of Bolts, Nuts, Rivets, Screws and Similar Fasteners
OFFICERS
R. P , Trowbridge, Chairman
F. V. Kupchak, Vice-Chairman
R. B. Belford, Secretary
AEROSPACE INDUSTRIES ASSOCIATION O F AMERICA
J . F. Cramer, T h e Boeing Company, S e a t t l e , Washington
S . J . Turek, Grumman Aircraft Engineering Corporation, Bethpage, L.I., N.Y.
AMERICAN INSTITUTE O F INDUSTRIAL ENGINEERS
R. T. Kelly, H i t c h c o c k P u b l i s h i n g Company, Wheaton, Illinois
AMERICAN SOCIETY F O R TESTING AND MATERIALS
J . W. Caum, American Society for T e s t i n g a n d Materials, P h i l a d e l p h i a , P a .
AMERICAN SOCIETY O F AGRICULTURAL ENGINEERS
F. C. Ewert, D e e r e & Company, Moline, Illinois
J . H. Zich, A l t e r n a t e , Ford Motor Company, Birmingham, Michigan
AMERICAN SOCIETY O F MECHANICAL ENGINEERS, T H E
A. R. Machell, J r - , Xerox Corporation, R o c h e s t e r , New York
E. P. T i s c h , Voi-Shan Manufacturing Company, Culver C i t y , California
ASSOCIATION O F AMERICAN RAILROADS RAIL-COMMITTEE
J. G. Britron, A s s o c i a t i o n of American Railroads R e s e a r c h C e n t e r , C h i c a g o , Illinois
C. C. Herrick, New York C e n t r a l S y s t e m , New York, New York
FARM AND INDUSTRIAL EQUIPMENT INSTITUTE
F. C. Ewert, D e e r e a n d Company; Moline, Illinois
INDUSTRIAL FASTENERS INSTITUTE
R. H. Akers, T h e National Screw a n d Manufacturing Company, Mentor, Ohio
R. B. Belford, Industrial F a s t e n e r s Institute, C l e v e l a n d , O h i o
A. R. Breed, T h e Lamson & S e s s i o n s Company, C l e v e l a n d , Ohio
S. D. Daniels, Standard P r e s s e d S t e e l Company, J e n k i n t o w n , P a .
D. A. Garrison, R u s s e l l , B u r d s a l l & Ward Bolt & Nut Company, C h i c a g o , Illinois
N. J. Gruca, Illinois T o o l Works, Inc., Elgin, Illinois
R. C. Kozlik, Nacional L o c k F a s t e n e r s , Rockford, Illinois
R. L. Riley, Bethlehem S t e e l Company, L e b a n o n , Pa.
L . E. S a r a z , JI., R e p u b l i c S t e e l Corporation, C l e v e l a n d , Ohio
L. G. Selden, Armco S t e e l Corporation, K a n s a s C i t y , Missouri
R. W. Groover, Alternate, ß e t h l e h e m S t e e l Company, L e b a n o n , Pa.
F. R. Ling, Alternate, R u s s e l l , B u r d s a l l & Ward Boit & Nut Company, Port C h e s t e r , N.Y.
C. B. Waud, A l t e r n a t e , Illinois T o o l Works, Inc., Elgin, Illinois
MFRS. STANDARDIZATION SOCIETY O F T H E VALVE AND FITTINGS INDUSTRY
J . R.'Welshman, Grinnell ,Corporation, Providence, Rhode I s l a n d
NATIONAL E L E C T R I C A L MANUFACTURERS ASSOCIATION
F. V. Kupchak, Westinghouse E l e c t r i c Corporation, P i t t s b u r g h , Pa.
J . B. Levy, G e n e r a l E l e c t r i c Company, S c h e n e c t a d y , New York
W. A . Samsonoff, Alternate, National E l e c t r i c a l Manufacturers A s s o c i a t i o n , New York, N.Y.
NATIONAL E L E V A T O R INDUSTRY, INC.
S. Seth Robens, Otis E l e v a t o r Company, New York, N.Y.
NATIONAL MACHINE TOOL BUILDERS' ASSOCIATION
D. R. Stoner, JI., L a n d i s Machine Company, Waynesboro, P a .
S E R V I C E TOOLS INSTITUTE
J. R. H a y n e s , J. H. Williams Company, Buffalo, New York
V
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S O C I E T Y O F AUTOMOTIVE ENGINEERS
D. R. Bowen, G e n e r a l Motors Corporation, Warren, Michigan
E. E. Heibeck, C h r y s l e r Corporation, Detroit, Michigan
K. G. Roth, Mack T r u c k s , Inc., Allentown, Pa.
R. P. Trowbridge, G e n e r a l Motors T e c h n i c a l C e n t e r , Warren, Michigan
J - H. Venema, F o r d Motor Company, Dearborn, Michigan
S O C K E T SCREW PRODUCTS BUREAU
E r n e s t Heldmann, Holo-Krome Company, Hartford, C o n n e c t i c u t
P a u l P i c k , A l l e n Manufacturing Company, Hartford W., C o n n e c t i c u t
TELEPHONE GROUP, T H E
M. C. Berryman, Western E l e c t r i c Company, Inc., C h i c a g o , I l l i n o i s
R. H. Van Hom, B e l l T e l e p h o n e Laboratory, C o l u m b u s , Ohio
F. P. Balacek, A l t e r n a t e , B e l l T e l e p h o n e Laboratory, Columbus, Ohio
TUBULAR & S P L I T R I V E T COUNCIL
R. M . Gordon, Milford Rivet & Machine Company, Milford, C o n n e c t i c u t
U S . D E P A R T M E N T OF T H E AIR F O R C E
F. L. C a l k i n s , A e r o n a u t i c a l S y s t e m s Div., Wright-Patterson A F B , Ohio
U.S. D E P A R T M E N T O F T H E ARMY
R. C. Engelmann, Army Weapons Command, R o c k I s l a n d , Illinois
R. F. Scherer, A l t e r n a t e , Army Weapons Command, Rock I s l a n d , Illinois
U.S. D E P A R T M E N T O F COMMERCE
J . R. R e e s , N a t i o n a l B u r e a u of S t a n d a r d s , Washington, D.C.
U.S. D E P A R T M E N T O F D E F E N S E
J . D. J o n e s , D e f e n s e Industrial Supply C e n t e r , P h i l a d e l p h i a , Pa.
Martin Betof, Alternate, D e f e n s e Industrial Supply C e n t e r , P h i l a d e l p h i a , Pa.
U.S. D E P A R T M E N T O F T H E NAVY
C. A. F u l e s d y , N a v a l S h i p S y s t e m s Command, U’ashington, D.C.
U.S. MACHINE, C A P , WOOD AND T A P P I N G SCREW BUREAUS
S. C. Adamek, P h e o l l Manufacturing Company, C h i c a g o , Illinois
R. M. Byrne, U.S. Screw S e r v i c e B u r e a u s , New York, N.Y.
T. J . Ferry, E. W. Ferry Screw P r o d u c t s Company, Inc., C l e v e l a n d , Ohio
Wilfred Kay, Parker-Kalon Corporation, Clifton, New J e r s e y
Herman Muenchinger, C o n t i n e n t a l Screw Company, New ßedford, Mass.
K. G. Ringland, C e n t r a l Screw Company, Keene, New Hampshire
C. C. Tucker, T h e R e e d & P r i n c e Manufacturing Company, Worcester, Mass.
L o u i s Z a n i n , E l c o I n d u s t r i e s , Inc., Rockford, Illinois
P a u l Foytho, A l t e r n a t e , Harvey tlubbel, Inc., Bridgeport, C o n n e c t i c u t
E , F. T a u s c h e r , A l t e r n a t e , P h e o l l Manufacturing Company, C h i c a g o , Illinois
INDIVIDUAL MEMBERS
H. C. Etdman, Shaker H e i g h t s , Ohio
F. E. Graves, Fairfield, C o n n e c t i c u t
L o u i s Oest, T e a n e c k , New J e r s e y
C. A. Wenne, Midland Screw Corporation, Chicago, Illinois
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9009275 0037046 5 3 3
Personnel of Subcommittee No. 2 on Square and Hex Bolts, Screws and Nuts
-
A. R. Machell, Jr., Chairman. Xerox Corporation, Xerox Square
Building 105, R o c h e s t e r , New York 14603
R. B. Belford, Secretary, Industrial F a s t e n e r s Institute, 1505 E a s t Ohio Building, 1717 E a s t 9 t h Street,
C l e v e l a n d , Ohio 441 1 4
S. C. Adamek, P h e o l l Manufacturing Company, 5700 West R o o s e v e l t Road, Chicago, Illinois 60650
E. F. T a u s c h e r , (alternate), P h e o l l Manufacturing Company, 5700 West R o o s e v e l t Road, C h i c a g o , Illinois 60650
R. H. Akers, T h e National Screw & Manufacturing Co., 8100 T y l e r Boulevard, Mentor, Ohio 44060
F. P. B a l a c e k , B e l l T e l e p h o n e L a b o r a t o r i e s , lnc., 6200 E a s t Broad S t r e e t , Columbus, Ohio 43213
D. T. Lipari, (alternate), B e l l T e l e p h o n e Laboratories, Inc., 6200 E a s t Broad S t r e e t , Columbus, Ohio 43213
A. G. Baustert, F e d e r a l Screw Works, 3401 Martin Avenue, Detroit, Michigan 48210
A. R. Breed, T h e L a m s o n & S e s s i o n s Co., 5000 T i e d e m a n Road, C l e v e l a n d , Ohio 44144
R. M. Byrne, U.S. Screw S e r v i c e Bureaus, 331 Madison Avenue, New ï o r k , New York 10017
R. C. Engelmann, Hdqs., U.S. Army Weapons Command, R o c k I s l a n d , Illinois 61201
O. M. Kelley, (alternate), Hdqs., U.S. Army Weapons Command, Rock Island, Illinois 61201
C. A. F u l e s d y , Head, S t a n d a r d i z a t i o n S o c i e t i e s L i a i s o n
C o d e S H I P S 06214, N a v a l S h i p S y s t e m s Command,
Washington, D.C. 20360
D. A. Garrison, R u s s e l l , B u r d s a i l & Ward Bolt a n d Nut Co., 3 3 North Dearborn Street, C h i c a g o , Illinois 60607
R. L. Getz, C a t e r p i l l a r T r a c t o r Company, Engineering T e c h n i c a l S e r v i c e s , E a s t P e o r i a , Illinois 6161 1
F. E. Graves, C o n s u l t a n t , P.O. Box 823, Fairfield, C o n n e c t i c u t 06430
R. W. Groover, Bethlehem S t e e l Corporation, L e b a n o n P l a n t , Lebanon, P e n n s y l v a n i a 17042
F. V. Kupchak. R e s e a r c h a n d Development Center, Westinghouse E l e c t r i c Corporation, P i t t s b u r g h , P e n n s y l vania 15235
C. S. Larson, Dept. of M e c h a n i c a l and Industrial Engineering, L n i v e r s i t y of Illinois, Urbana, Illinois 61801
J . B. Levy. G e n e r a l E l e c t r i c Company, 1 River Road
Building 36-413 S c h e n e c t a d y , New York 12305
H. G. Muenchinger, C o n t i n e n t a l Screw Company, 459 Mount P l e a s a n t S t r e e t , New Bedford, M a s s a c h u s e t t s 02742
J . R. R e e s , N a t i o n a l Bureau of S t a n d a r d s , Room A107, Building 220, Washington, D.C. 20234
S. S . Roberts, O t i s E l e v a t o r Company, 260 E l e v e n t h Avenue, New York, New York 10001
C. F. Schaening, G e n e r a l Motors Corporation, General Motors T e c h n i c a l Center, Warren, Michigan 18090
L. G. Selden, Armco Steel Corporation, 7000 R o b e n s Street, K a n s a s C i t y , Missori 64125
C. W. Stockwell, International H a r v e s t e r Company, 7 South 600 County L i n e Road, t l i n s d a l e , Illinois 60521
C. A. Weme, Midland Screw Corporation, 4045 S. Morgan Street, C h i c a g o , Illinois 60609
-
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9009275 0 0 3 7 0 4 7 45T
CONTENTS
Page
..............................................
..............................................
Square N u t s .
Table 1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Table 2 . . . . . . . . . . . . . . . . . . . . . . . . . . .
H e x Flat N u t s a n d H e x Flat J a m N u t s .
Introductory N o t e s
General Data . . . .
--`,,```,,,,````-`-`,,`,,`,`,,`---
Hex Nuts and Hex Jam Nuts .
Table 3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Hex Slotted N u t s .
Table 4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Hex Thick N u t s .
Table
5 .........................................
6 ....................................
H e x Thick Slotted Nuts .
Table
Table 7
Heavy Square Nuts .
.......................................
H e a v y H e x Flat N u t s a n d H e a v y H e x Flat J a m N u t s .
Table 8.
H e a v y H e x N u t s and H e a v y H e x J a m N u t s .
Table
.................
9 ........................
...................................
I .
H e x Castle N u t s . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
II .
Slot G a g e s a n d G a g i n g F o r S l o t t e d N u t s . . . . . . . . . . . . . . . . . . . . . . .
Heavy Hex Slotted Nuts .
T a b l e 10
Appendix
i
1
2
4
6
8
10
12
14
16
18
20
22
Appendix
Formulas for Nut Dimensions
A p p e n d i x III .
24
A p p e n d i x IV .
Wrench O p e n i n g s F o r N u t s
26
.............................
...............................
...
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9009275 0037048 39b
AN SI B18.2.2- 197 2
AMERICAN N A T I O N A L STANDARD
SQUARE AND HEX NUTS
1. Introductory Notes
1.1
I n c . , T w o P e n n s y l v a n i a P l a z a , N e w York, N e w
York 10001.
Scope
2. General Data
1.1.1 T h i s s t a n d a r d i s i n t e n d e d t o c o v e r t h e
c o m p l e t e g e n e r a l a n d d i m e n s i o n a l d a t a for t h e
v a r i o u s t y p e s of s q u a r e a n d h e x n u t s r e c o g n i z e d
a s “ A m e r i c a n N a t i o n a l S t a n d a r d ” . Also i n c l u d e d
a r e a p p e n d i x e s c o v e r i n g g a g i n g of s l o t s i n s l o t t e d
n u t s , w r e n c h o p e n i n g s for n u t s a n d f o r m u l a s o n
which dimensional d a t a a r e based. It should b e
understood, however, t h a t where q u e s t i o n s arise
c o n c e r n i n g a c c e p t a n c e of p r o d u c t , t h e d i m e n s i o n s
in t h e t a b l e s s h a l l govern over recalculation by
formula.
2.1 Width Across F l a t s
T h e width a c r o s s f l a t s of n u t s h a l l b e t h e
d i s t a n c e m e a s u r e d , p e r p e n d i c u l a r to t h e a x i s of
n u t , o v e r a l l b e t w e e n t w o opposite s i d e s of t h e
n u t i n a c c o r d a n c e w i t h t h e n o t e s on r e s p e c t i v e
d i m e n s i o n a l t a b l e s . For m i l l e d - f r o m - b a r n o n f e r r o u s n u t s , t h e t a b u l a t e d maximum ( b a s i c ) width
a c r o s s f l a t s d i m e n s i o n s may b e e x c e e d e d t o c o n form with t h e c o m m e r c i a l t o l e r a n c e s of d r a w n o r
r o l l e d bar s t o c k m a t e r i a l .
1.1.2 T h e i n c l u s i o n of d i m e n s i o n a l d a t a in
t h i s s t a n d a r d i s n o t i n t e n d e d to imply t h a t a l l of
the products described herein are stock production
s i z e s . C o n s u m e r s a r e r e q u e s t e d to c o n s u l t w i t h
m a n u f a c t u r e r s c o n c e r n i n g l i s t s of s t o c k p r o d u c tion s i z e s .
2.2 Nut Thickness
T h e nut t h i c k n e s s s h a l l b e t h e overall d i s t a n c e , m e a s u r e d p a r a l l e l t o t h e a x i s of n u t , from
t h e t o p of t h e n u t to t h e b e a r i n g s u r f a c e a n d s h a l l
i n c l u d e t h e t h i c k n e s s of t h e w a s h e r face w h e r e
provided.
1.2 Dimensions
All d i m e n s i o n s i n t h i s s t a n d a r d a r e i n i n c h e s ,
unless stated otherwise.
2.3 Threads
T h r e a d s s h a l l b e U n i f i e d S t a n d a r d , C l a s s 2B,
of t h e s e r i e s s p e c i f i e d i n t h e n o t e s o n r e s p e c t i v e
dimensional t a b l e s , in accordance with American
N a t i o n a l S t a n d a r d . ANSI B1.l.
1.3 Options
O p t i o n s , w h e r e s p e c i f i e d , s h a l l be at t h e d i s c r e t i o n of t h e m a n u f a c t u r e r u n l e s s o t h e r w i s e
a g r e e d u p o n by t h e m a n u f a c t u r e r a n d t h e purchaser.
2.4 Finish
U n l e s s o t h e r w i s e s p e c i f i e d , n u t s s h a l l be
supplied with a natural ( a s p r o c e s s e d ) finish, unp l a t e d or u n c o a t e d .
1.4 Terminology
For d e f i n i t i o n s of t e r m s r e l a t i n g to f a s t e n e r s
component features thereof u s e d in t h i s
standard, refer to American N a t i o n a l Standard,
G l o s s a r y of T e r m s for M e c h a n i c a l F a s t e n e r s ,
ANST B 18.12-1362.
or
2.5 Workmansh ip
N u t s s h a l l b e f r e e from b u r r s , s e a m s , l a p s ,
l o o s e s c a l e , irregular s u r f a c e s and any defects
affecting their serviceability.
1.5 Related Standards
--`,,```,,,,````-`-`,,`,,`,`,,`---
It s h o u l d be n o t e d t h a t s t a n d a r d s f o r s q u a r e
and hex head bolts and screws, machine s c r e w s
and machine screw nuts, and other related
f a s t e n e r s a r e p u b l i s h e d u n d e r s e p a r a t e cover a s
l i s t e d o n t h e b a c k s h e e t of t h i s s t a n d a r d .
2.6 Designation
Nuts s h a l l b e designated by the following
d a t a i n t h e s e q u e n c e s h o w n : N o m i n a l size ( f r a c tion o r decimal); threads p e r inch; product name;
material (including specification where n e c e s s a r y ) ; p r o t e c t i v e f i n i s h , i f r e q u i r e d . See e x a m p l e s
below:
1.6 Referenced Standards
C o p i e s of r e f e r e n c e d AS’ïM s t a n d a r d s m a y b e
o b t a i n e d from t h e A m e r i c a n S o c i e t y for T e s t i n g
a n d M a t e r i a l s , 1916 R a c e S t r e e t , P h i l a d e l p h i a ,
P e n n s y l v a n i a 19103.
- 13 Square Nut, Steel, Zinc Plated.
3 / 4 - 16 H e a v y H e x N u t , SAE G r a d e 5 S t e e l .
1/2
1.000 - 8 H e x T h i c k S l o t t e d N u t , C o r r o s i o n
Resistant Steel.
C o p i e s of r e f e r e n c e d S A E s t a n d a r d s may be
o b t a i n e d from t h e S o c i e t y of A u t o m o t i v e E n g i n e e r s ,
1
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AMERICAN NATIONAL STANDARD
SQUARE AND HEX NUTS
ANSI 618.22-1972
t
IG1
h
25O
A PP ROX.
Table
1 Dimensions of
I
F
Nominal S i z e
or
B a s i c Major Dia
of Thread
Width Across
Flats
Basic
7/16,
9/16
5/8
3/4
13/16
I
Max
Square Nuts
I
H
G
Width Across
Corners
I
Min
Basic
'
Max
I
Min
Max
0.438
0.562
0.625
0.750
0.425
0.547
0.606
0.728
0.619
0.795
0.884
1.061
0.584
0.751
0.832
1.000
7/32
17/64
21/64
3 /8
0.235
0.283
0.346
0.394
0.203
0.249
0.310
0.356
Min
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1/4
5/16
3/8
7/16
0.2500
0.3125
0.3750
0.4375
1/2
5/8
3/4
7 /8
0.5000
0.6250
0.7500
0.8750
1
1 1/8
1 5/16.
0.812
1.000
1.125
1.312
0.788
0.969
1.O88
1.269
1.149
1.414
1.591
1.856
1.082
1.330
1.494
1.742
7 /16
35/64
21/32
49 16'4
0.458
0.569
0.680
0.792
0.418
0.525
0.632
0.740
1
1 1/8
11/4
13/8
1 1/2
Se e
Notes
1 .o000
1.1250
1.2500
1.37 50
1.5000
1 i/2
111/16
1 7/8
2 1/16.
2 1/4
1.500
1.688
1.875
2.062
2.250
1.450
1.631
1.812
1.994
2.175
2.121
2.386
2.652
2.917
3.182
1.991
2.239
2.489
2.738
2.986
7 /8
1
1 3/32
1 13/64
1 5/16
0.903
1.030
1.126
1.237
1.348
0.847
0.970
1.062
1.169
1.276
8
I
3
I
I
For additional requirements refer t o notes on P a g e 3 and General D a t a on P a g e 1.
.
2
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9009275 0017050 T 4 4
AMERICAN NATIONAL STANDARD
SQUARE AND HEX NUTS
ANSI 618.22-1972
N o t e s to Table 1:
perpendicular to the a x i s of t h e threaded hole within
a tolerance of 3 d e g for 1 in. nominal s i z e nuts or
smaller, and 2 deg for nuts larger than 1 in,
( I ) Unification.
Bold type indicates products
unified dimensionally with British and C a n a d i a n
standards.
( 5 ) Concentricity of Tapped Hole. Axis of
tapped hole s h a l l be concentric with a x i s of nut body
within a tolerance equal t o 5 percent (10 percent F I R )
of t h e maximum width a c r o s s flats.
( 2 ) T o p s of Nuts. T o p s of nuts s h a l l be flat and
chamfered o r w a s h e r crowned. Diameter of t h e chamfer
circle s h a l l be e q u a l t o the maximum width a c r o s s
f l a t s within a tolerance of minus 15 percent. T h e surf a c e of the chamfer may be slightly convex or rounded.
(6) T h r e a d s . Threads s h a l l be Unified c o a r s e
thread s e r i e s (UNC s e r i e s ) , C l a s s 2 8 .
.
(8) Nominal Size. Where specifying nominal s i z e
in d e c i m a l s , z e r o s preceding the decimal and in the
fourth decimal p l a c e s h a l l be omitted.
( 4 ) Bearing Surface. Bearing s u r f a c e s h a l l be
3
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--`,,```,,,,````-`-`,,`,,`,`,,`---
( 7 ) Material. U n l e s s otherwise s p e c i f i e d , chemic a l and mechanical properties of s t e e l nuts s h a l l conform with ASTM AS63. Other material s h a l l be as
agreed upon by manufacturer and purchaser.
(3) Width A c r o s s F l a t s . Maximum width a c r o s s
flats s h a l l not be exceeded ( s e e exception in General
Data). N o t r a n s v e r s e s e c t i o n through the nut between
25 a n d 75 per c e n t of t h e a c t u a l nut t h i c k n e s s a s
measured from t h e bearing s u r f a c e s h a l l be l e s s t h a n
the minimum width a c r o s s f lacs
~
9009275 OOl17051 980 M
AMERICAN NATIONAL STANDARD
SQUARE AND HEX NUTS
ANSI B18.2.2-1972
rF-I
1"I-
R
Table 2 Dimensions of Hex F l a t Nuts and Hex Flat Jam Nuts
Width Across
Flats
or
Basic Major Dia
Of T h e a d
11/8
11/4
13/8
11/2
1.1250
1.2500
1.3750
1.5000
G
H
Hl
Width Across
Corners
Thickness
Hex Flat Nuts
Thickness
Hex Flat Jam Nuts
F
Nominal Size
Basic
Max
1 1 1 / 1 6 1.688
1 7/8
1.875
2 1/16 2.062
2 1/4
2.250
Min
Max
Min
1.631
1.812
1.994
2.175
1.949
2.165
2.382
2.598
1.859
2.066
2.273
2.480
Basic
1
1 3/32
113/64
1 5/16
Max
1.030
1.126
1.237
1.348
Min
0.970
1.062
1.169
1.276
For additional requirements r e f e r to notes on Page 5 and General Data on Page 1.
--`,,```,,,,````-`-`,,`,,`,`,,`---
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9009275 0037052 B I ?
AMERICAN NATIONAL STANDARD
SQUARE AND HEX NUTS
Notes to Table
ANSI 818.2.2-1972
junction of hex corners with chamfer s h a l l be permiss i b l e provided the width a c r o s s corners is within
s p e c i f i e d limits a t and beyond a d i s t a n c e e q u a l t o
17.5 percent of t h e basic thread diameter from the
chamfered face.
2:
( I ) Unification. Bold type indicates products
unified dimensionally with British and Canadian
standards
.
(6) Bearing Surface. Bearing surface s h a l l be flat
and perpendicular t o t h e a x i s of the threaded hole
within a tolerance of 2 deg.
( 2 ) Smaller S i z e s . For s i z e s 1/4 in. through 1
in., the nuts specified in T a b l e 3 a r e recommended.
(3) T o p s of Nuts. Tops of nuts s h a l l be fiat and
chamfered. Diameter of the chamfer circle s h a l l be
e q u a l t o the maximum width a c r o s s flats within a
tolerance of minus 1 5 p e r c e n t . T h e length of chamfer
at hex corners s h a l l b e from 5 t o 15 percent of t h e
basic thread diameter. T h e surface of chamfer may be
slightly convex or rounded.
(7) Concentricity of Tapped Hole. Axis of
tapped hole s h a l l be concentric with a x i s of nut body
within a tolerance equal t o 3 percent (6 percent FIR)
of the maximum width a c r o s s flats.
(4) Width A c r o s s F l a t s . Maximum width a c r o s s
flats s h a l l not be exceeded ( s e e exception in General
Data). No transverse s e c t i o n through the nut between
25 and 75 percent of the a c t u a l nut t h i c k n e s s a s
measured from the bearing surface s h a l l be l e s s than
the minimum width a c r o s s flats.
( 9 ) Material. Unless otherwise specified, chemic a l and mechanical properties of s t e e l nuts s h a l l conform with ASTM A563. Other materials s h a l l be a s
agreed upon by manufacturer and purchaser.
(8) Threads. Threads s h a l l be Unified c o a r s e
thread s e r i e s (UNC s e r i e s ) , C l a s s 2 B .
(10) Nominal Size. Where specifying nominal s i z e
in decimals, z e r o s preceding the decimal and in the
fourth d e c i m a l place s h a l l be omitted.
(5) C o m e r Fill. A rounding or l a c k of fill a t
5
--`,,```,,,,````-`-`,,`,,`,`,,`---
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_ _
m 9009275 0037053 753 m
AMERICAN NATIONAL STANDARD
SQUARE AND HEX NUTS
ANSI 818.2.2-1972
mwb-4 m
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. . . .
3 3 3 3
9009275 001705Y b 9 T H
AMERICAN NATiONAL STANDARD
SQUARE AND HEX NUTS
Noter to Table
3:
(1) Unification. Bold type indicates products
unified dimensionally w i t h British a n d C a n a d i a n
s t a n d a r d s , Unification of fine thread nuts i s limited
t o s i z e s 1 in. a n d smaller.
(2) Tops a n d Bearing S u r f a c e s of Nuts. N u t s in
s i z e s 5/8 in. nominal size a n d smaller s h a l l be double
chamfered. Larger size nuts s h a l l be double chamfered
or h a v e w a s h e r faced bearing surface a n d chamfered
top.
T h e diameter of chamfer c i r c l e on double
chamfered nuts a n d diameter of w a s h e r f a c e s h a l l be
within the limits of the maximum width a c r o s s flats
and 95 percent of the minimum width a c r o s s flats.
T h e tops of w a s h e r faced nuts s h a l l be flat
and t h e diameter of chamfer c i r c l e s h a l l be equal t o
t h e maximum width a c r o s s flats within a tolerance of
minus 15 percent. The length of chamfer at h e x corners
s h a l l b e from 5 to I 5 percent of t h e b a s i c thread d i a meter. The s u r f a c e of chamfer may be slightly convex
or rounded.
Bearing s u r f a c e s s h a l l be flat and perpendicular to the a x i s of the threaded hole within t h e FIR
limits s p e c i f i e d for the respective nut type and s t r e n g t h
level.
(3) Width A c r o s s F l a t s . Maximum width a c r o s s
f l a t s s h a l l not be exceeded ( s e e exception in General
Data). No t r a n s v e r s e s e c t i o n through t h e nut between
2 5 and 75 percent of the a c t u a l nut t h i c k n e s s a s
measured from the bearing s u r f a c e s h a l l be less t h a n
ANSI 618.2.2-1972
t h e minimum width a c r o s s flats.
(4) Cornet Fill. A rounding or l a c k of fill a t
junction of h e x cornets with chamfer s h a l l be permiss i b l e provided t h e width a c r o s s corners is within
s p e c i f i e d limits at a n d beyond a d i s t a n c e e q u a l to 17.5
p e r c e n t of the b a s i c thread diameter from the chamfered
faces.
( 5 ) Concentricity of Tapped Hole. Axis of tapped
hole s h a l l b e concentric with a x i s of nut body within a
tolerance equal t o 3 percenr (6 percent FIR) of t h e
maximum width a c r o s s flats.
(6) Countersink. Tapped hole shall be countersunk on t h e bearing f a c e or f a c e s . T h e maximum
countersink diameter s h a l l be t h e thread b a s i c
(nominal) major diameter plus 0.030 in. for 3/8 in.
nominal s i z e nuts and smaller, a n d 1.08 times t h e
b a s i c major diameter for nuts larger t h a n 3/8 'in. N o
part of the threaded portion s h a l l project beyond t h e
bearing s u r f a c e .
(7) Threads. Threads s h a l l be u n i f i e d c o a r s e ,
fine or 8 thread s e r i e s (UNC, UNI; or 8 U N s e r i e s ) ,
Class 2 ß .
(8) Material. U n l e s s otherwise s p e c i f i e d , chemic a l a n d mechanical properties of s t e e l nuts s h a l l conform with ASTM A i 6 3 , Grade A or SAE J995, Grade 2.
Other materials s h a l l be a s agreed upon by manufacturer and purchaser.
(9) Nominal Size. Where specifying nominal s i z e
in d e c i m a l s , zeros preceding the decimal and in t h e
fourth d e c i m a l place s h a l l be omitted.
--`,,```,,,,````-`-`,,`,,`,`,,`---
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~
~~
9009275 0017055 52b
AMERICAN NATIONAL STANDARD
SQüARE AND HEX NUTS
=
ANSI B18.2.2-1972
2
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~
9009275 00L705b 4 6 2
AMERICAN NATIONAL STANDARD
SQUARE AND HEX NUTS
ANSI B18.2.2-1972
( 4 ) Corner Fill. A rounding or lack of fill ac
junction of hex corners with chamfer s h a l l be permiss i b l e provided the width a c r o s s corners i s within
specified limits a t and beyond a d i s t a n c e e q u a l t o
17.5 percent of the b a s i c thread diameter from the
chamfered f a c e s .
Notes to Table 4:
(1) Unification. Bold type indicates products
unified dimensionaìly with British and C a n a d i a n
s t a n d a r d s . Unification of fine thread nuts i s limited to
s i z e s 1 i n . a n d under.
( 5 ) Concentricity of T a p p c d f i o l e . Axis of tapped
hole s h a l l be concentric with axis of nut body within
a tolerance equal t o 3 percent (6 percent FIR) of the
maximum width a c r o s s f l a t s .
(2) T o p s and Bearing Surfaces of Nuts. Nuts in
s i z e s 5/8 in. nominal s i z e a n d smaller s h a l l be double
chamfered. Larger s i z e nuts s h a l l be double chamfered
or have w a s h e r faced bearing surface a n d chamfered
top.
(6) Countersink. Tapped hole s h a l l be counters u n k on t h e bearing tace. The maximum countersink
diameter s h a l l be t h e thread basic (nominal) major
diameter plus 0.030 in. for 3/8 in. nominal s i z e nuts
and s m a l l e r , and 1.08 times the b a s i c major diameter
for nuts larger than 3/8 in. No part of the threaded
portion s h a l l project beyond t h e bearing s u r f a c e .
T h e diameter of chamfer c i r c l e o n double
chamfered nuts and diameter of w a s h e r face s h a l l be
within the limits of the maximum width a c r o s s flats
and 95 percent of t h e minimum width a c r o s s f l a t s .
T h e t o p of washer faced nuts s h a l l be flat
a n d the diameter of chamfer circle s h a l l be e q u a l t o
t h e maximum width a c r o s s flats within a tolerance of
minus 15 percent. T h e length of chamfer at h e x
corners s h a l l b e from 5 to 1 5 percent of t h e b a s i c
thread diameter. The s u r f a c e of chamfer may be slightly convex or rounded.
( 7 ) Slots. Slots s h a l l be nqrmai to nut f l a t s .
Contour of bottom of s l o t s s h a l l be a t manufacturer's
option. Requirements for gaging s l o t s a r e in Appendix
II.
(9) Material. U n l e s s otherwise s p e c i f i e d , chemic a l a n d mechanical properties of s t e e l nuts s h a l l conform with ASTM A563, Grade A or SAE J 9 9 5 , Grade 2 .
Other materials s h a l l be a s agreed upon by manufacturer a n d purchaser.
(3) Width A c r o s s F l a t s . Maximum width a c r o s s
flats s h a l l not be e x c e e d e d (see e x c e p t i o n in General
Data). N o transverse s e c t i o n through t h e nut between
25 and 75 percent of the a c t u a l nut t h i c k n e s s a s
measured from t h e bearing s u r f a c e s h a l l be l e s s than
t h e minimum width a c r o s s f l a t s .
(IO) Nominal Size. %'here specifying nominal s i z e
in d e c i m a l s , z e r o s preceding the decimal and in the
fourth decimal p l a c e s h a l l b e omitted.
9
Not for Resale
--`,,```,,,,````-`-`,,`,,`,`,,`---
(8) T h r e a d s . T h r e a d s s h a l l be Unified c o a r s e ,
fine or 8 thread s e r i c s ( U N C , G N F or 8 UN s e r i e s ) ,
C l a s s 2B.
Bearing s u r f a c e s h a l l be flat a n d perpendicular to t h e a x i s of the threaded hole within t h e
s p e c i f i e d FIR limit.
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=
_
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W 9009275 0037057 3 T î W
AM ER1CAN NATIONAL STAN DARD
SQUARE AND HEX NUTS
i
ANSI 818.2.2-1972
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Copyright ASME International
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_-
Not for Resale
AMERICAN NATIONAL STANDARD
SQUARE AND HEX NUTS
ANSI Bl&.2.2-197 2
Noter t o Table 5:
junction of hex corners with chamfer s h a l l be permiss i b l e provided the minimum width a c r o s s corners is
within specified limits a t a n d beyond a d i s t a n c e equal
to 17.5 percent of the b a s i c thread diameter from the
chamfered f a c e s .
(1) T o p s and Bearing Surfaces of Nuts. Nuts in
s i z e s 5/8 in. nominal s i z e and smaller s h a l l be
double chamfered. Larger size nuts s h a l l be double
Chamfered or have washer faced bearing surface and
chamfered top.
(4) Concentricity of Tapped Hole. Axis of tapped
hole s h a l l b e concentric with a x i s of nut body within a
tolerance equal to 3 percent (6 percent FIR) of the
maximum width a c r o s s flats.
T h e diameter of chamfer circle on double
chamfered nuts and diameter of washer f a c e s h a l l be
within t h e limits of t h e maximum width a c r o s s flats
and 95 percent of the minimum width a c r o s s f l a t s .
( 5 ) Countersink. Tapped hole s h a l l be counters u n k on the bearing face or f a c e s . T h e maximum
countersink diameter s h a l l be the thread b a s i c
(nominal) major diameter plus 0.030 in. for 31'8 in.
nominal size nuts and smaller, and 1.08 times t h e
basic major diameter for nuts larger than 3/8 in. No
part of the threaded portion s h a l l project beyond the
bearing s u r f a c e .
The tops of washer faced nuts s h a l l be flat
a n d t h e diameter of chamfer circle s h a l l be equal to
the maximum width a c r o s s f l a t s within a tolerance of
minus 15 percent. T h e length of chamfer at hex corners
s h a l l b e from 5 t o 15 percent of t h e basic thread d i a meter. T h e surface of chamfer may be slightly convex
or rounded.
(6) Threads. Threads s h a l l be Unified c o a r s e ,
fine or 8 thread s e r i e s (UNC, UNF or 8 UN s e r i e s ) ,
C l a s s 2B.
Bearing surfaces s h a l l be flat a n d perpendicular t o the a x i s of the threaded hole within the FIR
limits s p e c i f i e d for the respective strength level.
(7) Material. Unless otherwise specified, chemical and mechanical properties of s t e e l nuts s h a l l conform with ASTM A563, Grade A or SAE J995, Grade 2.
Other materials s h a l l be a s agreed upon by the manufacturer and purchaser.
( 2 ) Width Across Flats. Maximum width a c r o s s
flats s h a l l not be exceeded ( s e e exception in General
Data). No transverse s e c t i o n t h r o u b the nut between
25 and 75 percent of the a c t u a l nut t h i c k n e s s as
measured from t h e bearing s u r f a c e s h a l l be less than
the minimum width a c r o s s f l a t s .
(8) Nominal Size. Where specifying nominal s i z e
in decimals, z e r o s preceding the decimal and in the
fourth decimal p l a c e s h a l l be omitted.
--`,,```,,,,````-`-`,,`,,`,`,,`---
(3) Corner Fill. A rounding or lack of fill at
11
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-
H 9009275 0017059 171 M
AMERICAN NATIONAL STANDARD
SQUARE AND HEX NUTS
ANSI 618.2.2-1972
d
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Copyright ASME International
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Not for Resale
;4
W 9009275 O O L 7 0 b O 993
AMERICAN NATIONAL STANDARD
SQUARE AND HEX NUTS
ANSI 818.2.2-1972
Notes to Table 6 :
( 4 ) Corner Fill. A rounding or lack of fill at
junction of hex corners with chamfer s h a l l be permiss i b l e provided the width a c r o s s corners i s within
s p e c i f i e d limits a t a n d beyond a d i s t a n c e e q u a l t o
17.5 percent of t h e basic thread diameter from t h e
chamfered f a c e s .
(1) Unification. Bold type indicates products
unified dimensionally with British a n d C a n a d i a n
standards. Unification of fine thread products is
limited to s i z e s 1 in. and under.
( 5 ) Concentricity of Tapped Hole. Axis of tapped
hole s h a l l be concentric with a x i s of nut body within
a tolerance equal to 3 percent (6 percent FIR) of the
maximum width a c r o s s flats.
(2) T o p s and Bearing Surfaces of Nuts. Nuts in
s i z e s 5/8 in. nominal s i z e a n d smaller s h a l l be double
chamfered. Larger s i z e nuts s h a l l be double chamfered
or have washer faced bearing surface and chamfered
top.
(6) Countersink. Tapped hole s h a l l b e counters u n k on the bearing face. The maximum countersink
diameter s h a l l be t h e thread b a s i c (nominal) major
diameter plus 0.030 in. for 3/8 in. nominal s i z e nuts
and s m a l l e r , and 1.08 times the basic major diameter
for nuts larger than 3/8 in. No part of the threaded
portion s h a l l project beyond the bearing s u r f a c e ,
T h e diameter of chamfer circle on double
chamfered nuts a n d diameter of washer f a c e s h a l l be
within the limits of the maximum width a c r o s s flats
and 95 percent of t h e minimum width a c r o s s f l a t s .
The tops of washer faced nuts s h a l l be flat
a n d the diameter of chamfer c i r c l e s h a l l be e q u a l t o
the maximum width a c r o s s fiats within a tolerance of
minus 15 percent. T h e length of chamfer at h e x c o r n e r s
s h a l l be from 5 to 15 percent of t h e basic thread d i a meter. T h e s u r f a c e of chamfer may be slightly convex
or rounded.
(7) Slots. Slots s h a l l b e normal t o nut flats.
Contour of bottom of s l o t s s h a l l be a t manufacturer's
option. Requirements for gaging s l o t s a r e given i n
Appendix II.
( 3 ) Width A c r o s s F l a t s . Maximum width a c r o s s
flats s h a l l not be exceeded (see exception in General
Data). No transverse s e c t i o n through the nut between
25 and 75 percent of the a c t u a l nut t h i c k n e s s a s
measured from the bearing s u r f a c e s h a l l be l e s s than
the minimum width a c r o s s f l a t s .
(10) Nominal Size. Where specifying nominal s i z e
in decimals, z e r o s preceding the decimal and in the
fourth decimal place s h a l l be omitted.
13
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--`,,```,,,,````-`-`,,`,,`,`,,`---
(8) Threads. Threads s h a l l be Unified c o a r s e ,
fine or 8 thread s e r i e s (UNC, C"F of 8 UN s e r i e s ) ,
C l a s s 2B.
( 3 ) Material. Unless otherwise s p e c i f i e d , chemic a l and mechanical properties of s t e e l nuts s h a l l conform with ASTM A563, Grade A or SAE J995, Grade 2.
Other materials s h a l l be a s agreed upon by manufacturer and purchaser.
Bearing surface s h a l l be f l a t a n d perpendicular t o the a x i s of the threaded hole within the FIR
limits s p e c i f i e d for the respective strength level.
AMERICAN RATIOPiAL STANDARD
SQUAREANO H E X NUTS
ANSI B18.2.2-1972
P"1
25
APPROX.
Table
7
Dimensions of H e a v y Square Nuts
G
Nominal Size
Width Across
Flats
Or
Basic Major Dia
of Tbread
Max
Width Across
Corners
1
Min
Max
0.707
0.795
0.973
1.060
Min
0.670
1/4
0.750
0.919
1.000
5/16
3/8
7/16
0.266
0.330
0.393
0.456
0.218
0.280
0.341
0.403
1.167
1.416
1.394
1.237
1.503
1.768
2.033
1/2
5/8
3/4
7/8
0.520
0.647
0.774
0.901
0.464
O. 587
0.710
0.833
2.298
2.563
2.828
3.094
2.162
2.411
2.661
2.909
1
11/8
1 3/8
1.028
1.155
1.282
1.409
0.956
1 .O79
1.187
1.310
3.158
1 i/2
1.536
1.433
1 /2
9/16
1 1 /i6
3/4
0.562
0.688
0.750
0.546
0.669
0.728
1/2
5/8
3/4
7/8
0.5000
0.6250
0.7500
0.8750
7/8
1/16
1 1/4
1 7/16
0.875
1,062
1.250
1.438
0.850
1.031
1
1 1/8
11/4
1 3/8
1.0000
1.1250
1.2500
1.3750
1 5/8
1 13/16
2
2 3/16
1.625
1.812
2.000
2.188
1.575
1.756
1.938
2.119
1 1/2
1.5000
2 3/8
2.375
2.300
See
Notes
7
1
'
Th ic knes s
Max
0.2500
0.3125
0.3750
0.4375
1.212
3.359
Min
H
Basic
1/4
5/16
3/8
7/16
1
1
I
1
1.665
1.914
.
1 1/4
2
For additional requirements refer to notes on Page 1 5 and General Data on Page 1.
14
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Copyright ASME International
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Not for Resale
8'
~
9009275 0037062 766
AMERICAN NATIONAL STANDARD
SQUARE AND HEX NUTS
ANSI 618.2.2-1972
N o t e s to Table 7:
smaller, and 2 d e g for nuts larger than I in.
(1) T o p s of N u t s . Tops of nuts s h a l l be flat a n d
chamfered or washer crowned. Diameter of the chamfer
c i r c l e s h a l l he e q u a l to t h e maximum width a c r o s s
f l a t s within a tolerance of minus 15 percent. T h e surface of chamfer may be slightly convex or rounded.
( 4 ) Concentricity o f T a p p e d Hole. Axis of tapped
hole s h a l l be concentric with a x i s of nut body within a
tolerance equal t o 5 percent (10 percent FIR) of t h e
maximum width a c r o s s f l a t s .
( 5 ) Threads. T h r e a d s s h a l l be Lnified c o a r s e
thread s e r i e s (UNC s e r i e s ) , C l a s s 2B.
(2) Width A c r o s s F l a t s . Maximum width a c r o s s
fiats s h a l l not he exceeded ( s e e exception in General
Data). No transverse s e c t i o n through t h e nut between
25 and 75 percent of t h e a c t u a l nut t h i c k n e s s a s
measured from the hearing surface s h a l l be l e s s than
the minimum width a c r o s s flats.
(6) Material. U n l e s s otherwise s p e c i f i e d , chemic a l and mechanical properties of s t e e l nuts s h a l l conform with ASTM A 5 6 3 . Other materials s h a l l he a s
a g r e e d upon by manufacturer a n d purchaser.
( 3 ) Bearing Surface. Bearing s u r f a c e s h a l i he
perpendicular to the a x i s of the threaded hole within
a tolerance of 3 d e g for 1 in. nominal s i z e nuts a n d
( 7 ) Nominal Size. Where specifying nominal s i z e
in d e c i m a l s , z e r o s preceding the d e c i m a l and in t h e
fourth decimal place s h a l l he omitted.
--`,,```,,,,````-`-`,,`,,`,`,,`---
15
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9009275 00L70b3 b T 2
AMERICAN NATIONAL STANDARD
SQUARE AND HEX NUTS
ANSI 818.2.2-1972
o o ó ori
3-4333
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Copyright ASME International
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Not for Resale
3 3
mmr4r.Jmmmm-t
9009275 00170b4 539
AMERICAN NATIONAL STANDARD
SQUARE AND HEX NUTS
N o t e s to T o b l e
8:
( 1 ) Unification. Bold type indicates products
unified dimensionally with British and Canadian
standards.
( 2 ) Smaller S i z e s . For s i z e s 1 / 4 in. through 1
in., the nuts specified in T a b l e 3 a r e recommended.
(3) T o p s of Nuts. T o p s of nuts s h a l l be flat and
chamfered. Diameter of the chamfer c i r c l e s h a l l be
e q u a l t o the maximum width a c r o s s flats within a
tolerance of minus 15 percent. T h e length of chamfer
a t hex corners shall, be from 5 t o 1 5 percent of the
basic thread diameter. The surface of chamfer may be
slightly convex 01 rounded.
( 4 ) Width Across F l a t s . Maximum width a c r o s s
flats s h a l l not be exceeded ( s e e exception in General
Data). N o transyerse s e c t i o n through the nut between
25 and 15 percent of t h e a c t u a l nut t h i c k n e s s as
measured from the bearing surface s h a l l be l e s s than
the minimum width a c r o s s flats.
( 5 ) C o m e r Fill. A rounding or lack of fill a t
ANSI 618.2.2-1972
junction of hex corners with chamfer s h a l l be permiss i b l e provided the width a c r o s s comers i s within
s p e c i f i e d limits at and beyond a d i s t a n c e e q u a l t o
17.5 percent of t h e basic thread diameter from the
chamfered face.
(6) Bearing Surface. Bearing s u r f a c e s h a l l be flat
and perpendicular to the a x i s of the threaded hole
within a tolerance of 2 deg.
(7) Concentricity of Tapped Hole. Axis of
tapped hole s h a l l be concentric with a x i s of nut body
within a tolerance equal to 3 percent (6 percent FIR)
of the maximum width a c r o s s f l a t s .
(8) T h r e a d s . Threads s h a l l be Unified c o a r s e
thread s e r i e s (UNC s e r i e s ) , C l a s s 2B.
( 9 ) Material. Unless otherwise s p e c i f i e d , chemic a l and mechanical properties of s t e e l nuts s h a l l conform with ASTM A563. Other materials s h a l l be a s
agreed upon by manufacturer and purchaser.
(10) Nominal Size. Where specifying nominal s i z e
in d e c i m a l s , zeros preceding the decimal a n d in t h e
fourth decimal place s h a l l be omitted.
17
--`,,```,,,,````-`-`,,`,,`,`,,`---
Copyright ASME International
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No reproduction or networking permitted without license from IHS
m
Not for Resale
9 7007275 00170b5 475
=
AMERICAN NATIONAL STANDARD
SQUARE AND HEX NUTS
ANSI 818.2.2-1972
bo-N
m W n b C h d m n m dUco- n 3 c n T - t . W o P
mmmm e U T n nuub m m m o c
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9 9 9 9 999.9
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0 0 0 0 0 0 0 0 0 0 0 0 0 O 0 0 0 o o o o c
fT[mJ
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m m m v m m w r w o + m n m w t - c n o N n b o ~ n t . o
18
Copyright ASME International
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Not for Resale
W 9009275 0017066 301 W
AMERICAN NATIONAL STANDARD
SQUARE AND HEX NUTS
ANSI 818.2.2-1972
Notes to Table 9:
the minimum width a c r o s s flats.
( i ) Unification. Bold type indicates products
unified dimensionally with British and Canadian
standards. Unification of fine thread products i s
limited t o s i z e s 1 in. a d under.
(4) Corner Fill. A rounding or l a c k of f i l l at
junction of hex corners with chamfer s h a l l be permiss i b l e provided the width a c r o s s corners i s within
s p e c i f i e d limits a t and beyond a d i s t a n c e e q u a l t o
17.5 percent of t h e basic thread diameter from t h e
chamfered f a c e s .
--`,,```,,,,````-`-`,,`,,`,`,,`---
( 2 ) T o p s and Bearing Surfaces of Nuts. Nuts in
s i z e s 7/16 in. nominal s i z e and smaller s h a l l be
double chamfered. Larger s i z e nuts s h a l l be double
chamfered or have washer faced bearing s u r f a c e and
chamfered top.
(5) Concentricity of Tapped Hole. Axis of tapped
hole s h a l l be concentric with a x i s of nut body within
a tolerance equal to 3 percent (6 percent FIR) of t h e
maximum width a c r o s s f i a t s .
(6) Countersink. Tapped hole s h a l l be counters u n k on the bearing f a c e or f a c e s . T h e maximum
countersink diameter s h a l l be the thread basic (nominal)
major diameter plus 0.030 in. for 3 / 8 in. nominal s i z e
nuts and smaller, and 1.08 times the b a s i c major diameter for n u t s larger than 3/8 in. N o part of t h e
threaded portion s h a l l project beyond the bearing
surface.
The diameter of chamfer c i r c l e on double
chamfered nuts and diameter of washer f a c e s h a l l be
within the limits of t h e maximum width a c r o s s flats
and 95 per cent of the minimum width a c r o s s flats.
T h e tops of washer faced nuts s h a l l be fiat
and the diameter of chamfer circle s h a l l be equal t o
the maximum width a c r o s s flats within a tolerance of
minus 15 percent. T h e length of chamfer at h e x corners
s h a l l be from 5 to 15 percent of t h e b a s i c thread diameter. T h e s u r f a c e of chamfer may be slightly convex
or rounded.
(7) Threads. Threads s h a l l be Unified c o a r s e , fine
or 8 thread s e r i e s (UNC, UNF or 8 UN s e r i e s ) , C l a s s
2B. Unless otherwise s p e c i f i e d , coarse thread s e r i e s
s h a l l be furnished.
Bearing s u r f a c e s s h a l l be flat a n d perpenpendicular to the a x i s of the threaded hole within the
FIR limits specified for t h e respective nut type and
strength level.
(8) Material. Unless otherwise s p e c i f i e d , chemic a l a n d mechanical properties of s t e e l nuts s h a l l confmm with ASTM A563, Grade A or SAE 1995, Grade 2.
Other materials s h a l l be a s agreed upon by manufact urer a n d purchaser.
(3) Width Across F l a t s . Maximum width a c r o s s
flats s h a l l not be exceeded ( s e e exception in General
Data). No transverse s e c t i o n through the nut between
2 5 and 75 per c e n t of t h e a c t u a l nut thickness a s
measured from the bearing surface s h a l l be l e s s than
(9) Nominal Size. Where specifying nominal s i z e
in d e c i m a l s , zeros preceding the decimal and in the
fourth decimal place s h a l l be omitted.
19
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Not for Resale
W 9009275 O017067 2118 W
AMERICAN NATIONAL STANDARD
SQUARE AND HEX NUTS
ANSI 618.2.2-1972
~
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is
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Not for Resale
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-U
1 9009275 0037068 1 8 4 ' 1
AM ER1CAN NATIONAL STAN DARD
SQUARE AND HEXNUTS
Notes to T a b l e
ANSI 818.2.2-1972
10:
( i ) Unification. Bold type indicates products
unified dimensionally with British and C a n a d i a n
s t a n d a r d s . Unification of fine thread products i s
limited to s i z e s 1 in. a n d under.
( 2 ) T o p s a n d Bearing Surfaces of Nuts. Nuts i n
s i z e s 7/16 in. nominal s i z e a n d s m a l l e r s h a l l be
double chamfered. Larger s i z e nuts s h a l l be double
chamfered or have w a s h e r f a c e d bearing s u r f a c e and
chamfered top.
T h e diameter of chamfer c i r c l e on double
chamfered nuts a n d diameter of washer face s h a l l be
within t h e limits of the maximum width a c r o s s flats
and 95 percent of the minimum width a c r o s s f l a t s .
The t o p s of w a s h e r f a c e d nuts s h a l l be f l a t
and t h e diameter of chamfer c i r c l e s h a l l be e q u a l t o
the maximum width across flats within a tolerance of
minus 15 percent. T h e length of chamfer a t hex corners
s h a l l be from 5 t o 15 percent of t h e b a s i c thread diameter. T h e surface of chamfer may be slightly convex
or rounded.
Bearing surface s h a l l be flat and perpendicular to t h e a x i s of t h e threaded hole within the FIR
limits s p e c i f i e d for the respective strength l e v e l .
junction of hex corners with chamfer s h a l l b e permiss i b l e provided t h e width a c r o s s corners i s within
s p e c i f i e d limits a t and beyond a d i s t a n c e e q u a l to
17.5 percent of the b a s i c thread diameter from t h e
chamfered faces.
( 5 ) Concentricity of T a p p e d Hole. Axis of tapped
h o l e s h a l l be concentric with axis of nut body wichin
a tolerance e q u a l t o 3 percent (6 percent F I R ) of t h e
maximum width a c r o s s flats.
( 6 ) Countersink. Tapped hole s h a l l be counters u n k on the bearing face. The maximum countersink
diameter s h a l l be t h e thread b a s i c (nominal) major
diameter p l u s 0.030 in. for 3/8 in. nominal s i z e n u t s
and smaller, and 1.08 times t h e b a s i c major diameter for
nuts larger t h a n 3/8 in. No part of the threaded portion
s h a l l project beyond t h e bearing s u r f a c e .
(7) Slots. Slots s h a l l be normal to nut f l a t s .
Contour of bottom of s l o t s s h a l l be a t manufacturer's
option. Requirements for gaging s l o t s a r e given i n
Appendix Il.
(8) Threads. Threads s h a l l be Unified c o a r s e ,
fine or 8 thread s e r i e s (UNC, UNF or 8 UN s e r i e s ) ,
C l a s s 2B. U n l e s s otherwise s p e c i f i e d , c o a r s e thread
s e r i e s s h a l l be furnished.
( 9 ) Material. U n l e s s otherwise s p e c i f i e d , chemic a l a n d mechanical properties of s t e e l nuts s h a l l
conîorm with ASTM A563, Grade A o r SAE J995, Grade
2 . Other materials s h a l l be a s agreed upon by manufacturer a n d purchas e r .
(3) Width A c r o s s Flats. Maximum width a c r o s s
flats s h a l l not be e x c e e d e d ( s e e exception in General
Data). No t r a n s v e r s e s e c t i o n through the nut between
25 and 75 percent of t h e a c t u a l nut t h i c k n e s s a s
measured from t h e bearing surface s h a l l be l e s s t h a n
the minimum width a c r o s s flats.
(10) Nominal Size. "here specifying nominal s i z e
in d e c i m a l s , z e r o s preceding the d e c i m a l and in the
fourth decimal place s h a l l be omitted.
( 4 ) C o m e r Fill. A rounding or l a c k of fill a r
21
--`,,```,,,,````-`-`,,`,,`,`,,`---
Copyright ASME International
Provided by IHS under license with ASME
No reproduction or networking permitted without license from IHS
Not for Resale
9009275 0037069 010
APPENDIX
=
I
HEX CASTLE NUTS
mwr-mch
o - m m
b O m - 0
. + r ( - d -
N N N N
~ m m r n w
0 0 0 0 0
O 0 0 0
o o o o c
99999 9999 9999c
-Q
i
O
W
.."".Y?.?
~
0 0 0 0 0
m
~ - w
N b
m m m ~ a
O 0 0 0
0 0 0 3 -
tC4.95
X
O
a
U)
+
3
3
C I -
hl
N
m -
Z
al
c
U)
O
V
X
P)
I
Y
O
U)
C
.-O
U)
C
P"1
.-E"
a
o i r i o m o
ohliAr.0
m o o 0 00000
Nirion 0 i A o m o
mCIt-mo
wmmr.
0 0 0 0 0
O 0 0 0
.??Y??q.."..
ONiT\r.O
?Y.??
C.cICI4-
C I C I C I C I 3
22
Copyright ASME International
Provided by IHS under license with ASME
No reproduction or networking permitted without license from IHS
Not for Resale
--`,,```,,,,````-`-`,,`,,`,`,,`---
ööööö oöoo oöoöc
9009275 0017070 832
=
HEX CASTLE NUTS (Cont’d)
Notes to Appendix I:
Diameter of chamfer circle and diameter of w a s h e r
face s h a l l be within t h e limits of the maximum width
a c r o s s f l a t s and 95 percent of the minimum width
a c r o s s flats. T h e length of chamfer a t hex corners
s h a l l be from 5 to 15 percent of t h e b a s i c thread
diameter. T h e surface of chamfer may be slightly
convex or rounded. Bearing surface s h a l l be flat a n d
perpendicular to t h e a x i s of the threaded hole within
t h e s p e c i f i e d FIR limit.
(1) THESE NUTS ARE NOT RECOMMENDED
FOR NEW DESIGNS.
( 2 ) Slots. S l o t s s h a l l be normal t o nut f l a t s .
Contour of bottom of s l o t s s h a l l be a t manufacturer’s
option. Requirements for gaging s l o t s a r e given in
Appendix II.
(3) Cylindrical P a r t . Maximum diameter of cylindrical part s h a l l not exceed maximum width a c r o s s
flats.
(4) Height of Hex. Height of t h e hex is measured
from the bearing surface t o t h e t o p of arc.
( 5 ) Width Across F l a t s . Maximum width a c r o s s
flats s h a l l not be exceeded ( s e e exception in General
Data). No transverse s e c t i o n through the hex portion
of the nut between 25 and 75 percent of the actual uns l o t t e d t h i c k n e s s a s measured from the bearing s u r f a c e
s h a l l be l e s s than the minimum width a c r o s s flats.
( 6 ) Corner Fill. A rounding or lack of f i l l a t
junction of hex corners with chamfer s h a l l be permiss i b l e provided the width a c r o s s corners i s within
s p e c i f i e d limits at and beyond a d i s t a n c e equal t o
17.5 percent of t h e b a s i c thread diameter from both
the bearing face a n d the junction of top of h e x f a c e s
with c a s t l e fillet.
(7) Bearing Surface. Bearing surface of nuts in
s i z e s 5/8 in. nominal s i z e and smaller s h a l l have
chamfered corners. Bearing surface of larger s i z e nuts
s h a l l be washer faced or have chamfered corners.
(9) Countersink. Tapped hole s h a l l be counters u n k on t h e bearing face. T h e maximum countersink
diameter s h a l l be the thread b a s i c (nominal) major
diameter plus 0.030 in. for 3/8 in. nominal size nuts
and s m a l l e r , and 1.08 times the basic major diameter
for nuts larger than 3/8 in. No part of the threaded
portion s h a l l project beyond the bearing s u r f a c e .
(10) Threads. Threads s h a l l be Unified c o a r s e or
fine thread s e r i e s (UNC or UNF s e r i e s ) , C l a s s 2 8 .
U n l e s s otherwise s p e c i f i e d , fine thread s e r i e s w i l l be
furnished.
(11) Material. Chemical and mechanical properties
of nuts s h a l l be a s agreed upon by manufacturer and
purchaser.
( 1 2 ) Nominal Size. Where specifying nominal s i z e
in decimals, zeros preceding the decimal and in the
fourth decimal place s h a l l be omitted.
23
Copyright ASME International
Provided by IHS under license with ASME
No reproduction or networking permitted without license from IHS
Not for Resale
--`,,```,,,,````-`-`,,`,,`,`,,`---
(8) Concentricity of Tapped Hole. Axis of tapped
hole s h a l l be concentric with a x i s of nut body within a
tolerance equal to 3 percent (6 percent FIR) of the
maximum width a c r o s s flats.
~
= 9009275 0017071 779
APPENDIX II
SLOT GAGES AND GAGING FOR SLOTTED NUTS
The gages specified below shall be used to determine the acceptability of the alignment and bottom
contours of the slots in slotted nuts in accordance
with the following procedure:
The gaging for slot alignment provides for equal
variations in the location of the cotter pin hole in
bolt and the location of the slots in nut.
To inspect the nut, the slotted end of gage shail
be inserted through the threaded hole from the bearing surface of the nut. The gage pin shaii then be
inserted into both the gage slot and the nut slots
through three adjacent faces of nut, consecutively.
Slot alignment shall be considered satisfactory if the
gage pin fits into the slots without interference at all
three gaging positions. The bottom contour shail be
acceptable if the gage pin contacts the bottom surfaces of opposite slots during the alignment gaging
at ail three positions.
Some deviations from the specified gage plug diameters D may be necessary to compensate for variations in the nut thread minor diameter due to differences in manufacturing practices.
To insure adequate service life, gages and gage pins
shall be suitably hardened.
CONTOURBEYOND THIS
FACE OPTIONAL
PIN MUST BE ROUND
AND STRAIGHT FOR
THIS LENGTH
CONTOUR OF HEAD
OPTIONAL
HOLE FOR ATTAC
PIN TO GAGE
GAGE PIN
GAGE
A
Nominal Size
or
B a s i c Major Dia
of Thread
D'
Gage
Pilot
Length
Plug
Min
Max
Gage Plug
Diameter
Face
I
E
I:
G
H
Gage
Pilot
Diameter
Gage
Slot
Width
Gage
Pin
Diameter
Gage
Pin
Length
to.ooo
Min
Coarse
Thread
Fine
Thread
Min
to.ooo
to.ooo
-0.001
-0.001
O. 196
0.252
0.307
0.360
0.211
0.267
0.330
O. 383
0.181
0.237
0.292
0.345
0.065
0.085
0.115
0.115
10.005
114
5/16
318
7/16
0.2500
0.3125
0.3750
0.4375
0.288
O. 3.16
0.415
0.463
0.110
0.150
0.180
0.200
0.375
0.406
0.500
0.562
112
9/16
518
314
718
1
1-118
1-114
1-318
i-112
0.5000
0.5625
0.6250
0.7500
0.8750
1.0000
1.1250
1.2500
1.3750
1.5000
0.573
0.621
0.731
0.827
0.922
0.260
0.280
0.310
0.370
0.480
0.625
0.703
0.781
O. 938
1.109
0.417
0.472
0.527
0.642
0.755
O. 446
0.502
0.565
0.682
0.798
0.402
0.457
0.512
0.627
0.740
1.018
1.272
1.399
1.526
0.550
0.600
0.660
0.770
0.810
1.250
1.406
1.562
1.718
1.875
0.865
0.970
1.095
1.195
1.320
0.910
1.035
1.160
1.285
1.410
1-314
2
2-114
2-112
2-314
1.7500
2.0000
2.2500
2.5000
2.7500
1.759
2.013
2.251
2.505
2.759
1.190
1.370
1.610
1.730
1.980
2.188
2.500
2.818
3.125
3.438
1.534
1.759
2.009
2.229
2.479
3
3-114
3-112
3-314
3.0000
3.2500
3.5000
3.7500
4.0000
3.013
3.252
3.506
3.760
4.014
2.160
2.400
2.640
Z.890
3.140
3.750
4.062
4.37 5
4.688
5.000
2.729
2.979
3.229
3.479
3.729
4
1.176
,..
...
...
...
.. .
...
...
...
...
...
4.0.002
-0.000
-0.002
0.065
0.115
0.115
1.00
1.06
1.19
1.25
0.145
0.145
0.175
0.175
0.175
0.145
0.145
0.175
0.175
0.175
1.38
1.44
1.56
1.75
1.94
0.850
0.955
1.080
1.180
1.305
0.235
0.235
0.305
0.305
0.365
0.235
0.235
O. 305
0.305
0.365
2.12
2.31
2.50
2.69
2.88
1.519
1.744
1.994
2.214
2.464
0.425
0.425
0.425
0.425
0.545
0.425
0.425
0.425
0.425
O. 545
3.25
3.62
4.00
4.38
4.75
2.7 14
2.964
3.214
3.464
3.714
0.615
0.615
0.615
0.615
0.615
0.615
0.615
0.61 5
0.61 5
0.61 5
5.12
5.50
5.88
6.25
6.62
O.Os5
--`,,```,,,,````-`-`,,`,,`,`,,`---
Dimensions of Slot Gages and Gage Pins
1Diameters tabulated are equivalent to the minimum minor diameters of Class 28 threads. I f the nuts are not threaded with Unified coarse
(UNC) or fine (UNF) threads, the diameter of gage shall be the same as the diameter of the GO thread plug gage for the bore.
Copyright ASME International
Provided by IHS under license with ASME
No reproduction or networking permittedo.
without license from IHS
2
Not for Resale
~
~
~
._ .
_
_
~
~~
-~
9009275 0037072 6 0 5
APPENDIX 111
FORMULAS FOR NUT DIMENSIONS
-~
-1
~
Nut Size
Nut Type
1/4 thru
Hcx Fiat
H = 0.875 D
o.o16
0.050 D
H = 0.875 D
o.o16
I
I
1
1 1 / 8 thru 1 1/2 F = 1.500D
I 1/8
Hex Flat
Jam
~
~-~
~
Width Across Comers
Nut Thickness
5/8 F = 1.500D + 0.062 0.050 D
3/4 thru 1 1/2 F = 1.500D
I
~
Tolerance
(Minus)
Basic
Square
---
Width Across Flats
I
1
+
+
o-o12
o.o12
0.050 D
H = 0.500D + 0.062 0.016 D + 0.012
1 1/4 thru 1 112 F = 1.500 D
0.050 D
H = 0.500D
+ 0.125 0.016 D + 0.012
F = 1.500D + 0.062 0.015 D + 0.00f H = 0.875 D
0.015 D + 0.003
0.015 D + 0.0Of
H = 0.875 D
3/4 thru 1 1/8 F = 1.500D
0.050D
H = 0.875 D - 0.016 0.016 D + 0.012
1 1/4 thru 1 1/2 F = 1.500D
0.050 D
H = 0.875 D
5/16 thru
Hex and
Hex Slotted
I
1/4
5/16 thru
518 F = 1.500D
M~ G = 1 . 1 5 4 7 ( ~F)~ ~
Min = 1'14(Min
0.015D+ Oeoo3
- 0.031
Max G = 1.1547(Max F)
Min G = 1.14(MinF)
0.016D + 0.012
I F = 1.500 D + 0.062 I 0.015 D + O.OO(
H = See Table
0.015 D + 0.003
0.015 D + O.OO(
H = See Table
D+
0.050 D
H = 0.500D + 0.047 0.016 D + 0.012
I 0.050 D
H = 0.500 D + 0.094 0.016 D + 0.012
5/8 F = 1.500D
Min G = 1.373(Min F)
0.050 D
F = 1.500D
1/4
Max G = 1.4142(Max F)
Max G = 1.1547(Max F)
Min G = 1.14 (Min F)
Hex Jam
3/4 thru 1 1/8 F = 1.500 D
I
I l 1/4 thru 1 1/2 F = 1.500D
0.015 D + 0.003
H = See Table
and Hex
314 thru 1 1/2 F = 1.500D
Heavy Square
1/4 thru 1 1/2 I: = 1.500 D + 0.125 0.050 D
Heavy
FlatHex
Max G = 1.1547(Max F)
~i~ G = 1-14 ( ~ F) i ~
H = See Table
Slotted
11 1 / 8 t h r u 4
0.050 D
H = See Table
10.015 D + 0.003
o.o16
H = 1.000D
HD
= 1.000D
~F=~.~OOD+O.~~~/O.O~O
Max G = 1.414ZMax F)
Min G = 1.373(MinF)
+
o.o12*
I
1/4 thru 1 1/8 F = 1.500D + 0.125 0,050D
Heavy Hex
Flat Jam
F = 1.500 D + 0.125 0.050 D
1 1/4 thru 2
F = 1.500D + 0.125 0.050D
2 1/4 thru 3
F = 1.500 D + 0.125 0.050 D
3 1/4 t h r u 4
F = 1 . 5 0 0 D + 0.125 0.050D
1 1/4 thru 2
I
2 l/4
I
H = 1.000D - 0.016 0.016 D + 0.012
M ~ ~ 1G. 1 5=4 7 ( M a x ~ )
Min G = 1.14(Min F)
1/4 thru I 1/8 F = 1.500 D + 0.125 0.050 D
Heavy Hex
Jam
Max G = 1.1547(Max F)
Min G = 1.14(MinF)
Max G = 1.1547(Max F)
H = 0 . 5 0 0 D + 0 . 1 2 5 0.016D+0.012** Min G = l.14(MinF)
H = 0.500D + 0.250 0.016 D + 0.012**
1/4 thru 1 1/8 F = 1.500D+ 0.125 0.050D
Heavy Hex
and
Heavy Hex
Slotted
I
H = 0 . 5 0 0 D + 0 . 0 6 2 ~ 0 . 0 1 6 D +0.012**
1 1/4 thru 2 1/4 I:= 1.500D + 0.125 0.050D
2 112 thru 4
I
H
F = 1.500 D + 0.125 0.050 D
=
0.500D + 0.047 0.016 D + 0.012
H = 0.500 D + 0.094 0.016 D + 0.012
I F = 1.500D + 0.125 I0.050D
H = 0 . 5 0 0 D + 0 . 0 7 8 0.016D+0.012
Max G = 1.1547(Max F)
Min G=1.14(MinF)
I
2 1/2 thru 3
F = 1.500 D + 0.125 0.050 D
3 1/4 thru 4
F = 1.500D + 0.125 0.050D
I
H = 0.500D + 0.203 0.016 D + 0.012
H = 0 . 5 0 0 D + 0 . 1 8 8 0 . 0 1 6 D + 0.012
1Adjusted to sixteenths.
21/4 thru 1 in. sizes adjusted to sixty-fourths. 1 1/8 thru 2 1/2 in. sizes adjusted upward to thirty-seconds. 2 3/4 thru 4 in. sizes adjusted
upward to sixteenths.
*Plus tolerance only. Minus tolerance adjusted so that minimum thickness is equal to minimum thickness of Heavy Hex Nut.
'"Plus tolerance only. Minus tolerance adjusted so that minimum thickness is equal to minimum thickness of Heavy Hex Jam Nut.
Where: D = Nominal nut size or basic diameter of the thread.
F = Width across flats.
G = Width across corners.
25
Copyright ASME International
Provided by IHS under license with ASME
No reproduction or networking permitted without license from IHS
Not for Resale
--`,,```,,,,````-`-`,,`,,`,`,,`---
I -
9009275 0017073 541
=
WRENCH OPENINGS FOR NUTS
Nominal Size
of Wrench’
also B a s i c
(Maximum) Width
A c r o s s Flats
of N u t s
Allowance
between
Nut F l a t s
and Jaws
of Wrench
Hex F l a t
Hex Flat J a m
Hex
Wrench Openings
Square Nut
Hex
Hex
Hex
Hex
Hex
Jam
Slotted
Thick
Thick Slotted
Castle
0.004
To12
0.006
0.006
0.007
0.007
0.007
Max
0.446
0.510
0.573
0.636
0.699
0.7500
0.8125
0.8750
0.9375
0.005
0.005
0.005
0.006
0.755
0.818
0.880
0.944
0.008
0.008
0.008
0.009
0.763
0.826
0.888
0.953
1
1 1/16
1 1/8
1 1/4
1 .o000
1.0625
1.1250
1.2500
0.006
0.006
0.007
0.007
1.006
1.068
1.132
1.257
0.009
0.009
0.010
0.010
1.015
1.077
1.142
1.267
.,.
1 5/16
1 3/8
1 7/16
1.3125
1.3750
1.4375
0.008,
0.008
0.008
1.320
1.383
1.446
0.011
0.011
0.011
1.331
1.394
1.457
.. .
..,
...
...
1
1
1
1
1
1.5000
1.6250
1.6875
1.8125
1.8750
0.008
0.009
0.009
0.010
0.010
1.508
1.634
1.696
1.822
1.885
0.012
0.012
0.012
0.013
0.013
1.520
1.646
1.708
1.835
1.898
1
1
7/16
2.0000
2.0625
2.1875
2.2500
2.3750
2.4375
0.011
0.011
0.012
0.012
0.013
0.013
2.011
2.074
2.200
2.262
2.388
2.450
0.014
0.014
0.015
0.015
0.016
0.016
2.025
2.088
2.215
2.277
2.404
2.466
2 9/16
2 5/8
2 3/4
2 13/16
2 15/16
2.5625
2.6250
2.7500
2.8125
2.9375
0.014
0.014
0.014
0.015
0.016
2.576
2.639
2.766
2.827
2.954
0.017
0.017
0.017
0.018
0.019
2.593
2.656
2.783
2.845
2.973
3
3 1/8
3 3/8
3 1/2
3 3/4
3 7/8
3.0000
3.1250
3.3750
3.5000
3.7500
3.8750
0.016
0.017
0.018
0.019
0.020
0.020
3.016
3.142
3.393
3.518
3.770
3.895
0.019
0.020
0.021
0.022
0.023
0.023
3.035
3.162
3.414
3.540
3.793
3.918
4 1/8
4 1/4
4 1/2
4 5/8
4 7/8
4.1250
4.2500
4.5000
4.6250
4.8750
0.022
0.022
0.024
0.024
0.025
4.147
4.272
4.524
4.649
4.900
0.025
0.025
0.026
0.027
0.028
4.172
4.297
4.550
4.676
4.928
5
1/4
5 3/8
5 5/8
5 3/4
6
5.0000
5.2500
5.3750
5.6250
5.7500
6.0000
0.026
0.027
0.028
0.029
0.030
0.031
5.026
5.277
5.403
5.654
5.780
6.031
0.029
0.030
0.031
0.032
0.033
0.034
5.055
5.307
5.434
5.686
5.813
6.065
6
6.1250
0.032
6.157
0.035
6.192
2
2
2
2
2
2
0.4375
0.5000
0.5625
0.6250
0.6875
0.003
0.004
0.004
3/4
13/16
7/8
15/16
1/2
5/8
11/16
13/16
7/8
1/16
3/16
1/4
3/8
5
1/8
0.004
Heavy
Heavy
Heavy
Heavy
Hex F l a t J a m
Hex
Hex J a m
Hex Slotted
Nominal Nut Sizes
Min
0.440
0.504
0.566
0.629
0.692
7/16
1/2
9/16
5/8
11/16
Heavy Square
Heavy Hex Flat
1/4
5/16
3/8
1/4
5/16
...
...
.. .
7/16
1/2
7/16
3/8
1/2
7/16
...
.. .
..-
. ..
9/16
5/8
..,
5/8
...
..*
3/4
3/4
1/2
9/16
...
5/8
,.-
...
7/8
...
1 1/8
...
. ..
1/4
5/16
3/8
. ..
3/4
...
7/8
...
...
7/8
* .
1
...
1 1/8
.. .
.
1 1/8
1 i/4
1 1/4
...
...
...
...
1 1/4
1 3/8
1 3/8
1 1/2
.. .
.. .
-..
...
.. .
...
a . .
...
...
,..
...
.
I
.
...
...
e . .
.. .
...
.._
. ..
. ..
. ..
..
...
e
.
.
.,.
...
...
13/8
11/2
. ..
1 1/2
...
...
...
...
-..
1 5/8
...
.. .
1 3/4
,..
1 7/8
...
.
.
I
.,.
...
...
.
I
.
...
...
...
...
...
...
.-.
...
-..
...
._.
..<
* .
.
...
...
2
...
2 1/4
- ..
2 1/2
...
2 3/4
...
3
.. .
3 1/4
3 1/2
3 1/2
3 3/4
3 3/4
4
4
iwrenches shall t marked with the “Nominal Size of Wrench” which i s equal to the basic (maximum) width across
flats of the correspc ding nut.
allowance (minir im clearance) between maximum width across flats of rhe nut and laws of wrench equals (0.0OSU’ t
0.001). Tolerance or
--`,,```,,,,````-`-`,,`,,`,`,,`---
26
Copyright ASME International
Provided by IHS under license with ASME
No reproduction or networking permitted without license from IHS
Not for Resale
= 7007275 0037074
488
AMERICAN NATIONAL STANDARDS FOR SCREW THREADS.
BOLTS. NUTS. RIVETS. SCREWS AND SIMILAR FASTENERS
....................................................
81.1-1960
....................................... 81.10-1968
Goges and Gaging for Unified Screw Threads ..................................... 81.2-1966
81.7-1965
Threods ........................
Nomencloture. Definitions. and Letter Symbols for
Unified Minioture
Threads .............................................
81.10-1958
Microscope Obiective Thread ................................................
81.11-1958
5 Interference .Fit Thread ............................................
81.12-1963
S m a l l Solid Rivets (7/16 Inch Nominal Diorneter and Smoller) ..........................
818.1.1-1972
(1/2 Inch Nominal Diometei and Lorger)...............................
818.1.2-1972
Square ond
ond Screws ............................................
818.2.1-1972
and
Nuts .................................................... 818.2.2-1972
Socket Cop. Shoulder ond
.......................................... 818.3-1969
Round Hcod Bolts ...................................................... 818.5-1971
........................................................818.6.1-1972
Wood
..........818.6.2-1972
Slotted Head Cop
Heod
ond Slotted Heodiesr Set
Unified Screw Threads
Unified
Screw
Threads-Metric Tionslotion
Screw
Screw
Class
Lorge R i v e t s
Hex Bolts
Hex
Squore
Set Screws
Screws. Square
Set Screws.
Screws
.......................................
Slotted and Recessed Head Tqpping Screws and Metollic Drive Screws ....................
Mochine
Screws
ond Mochine Screw Nuts
Generol Purpose Semi-Tubulor Rivets. F u l l Tubulor Rivets. Split Rivets and R i v e t Cops
Plow Bolts
....................................................
........
818.6.3-1972
618.6.4-1966
818.7-1966
818.9-1958 (R-1971)
....................................................
818.10-1963
.......................................................
618.11-1961
Glossary of Terms for Mechonicol Fasteners .....................................
818.12-1962
and Washer Assemblies .Sems .........................................
818.13-1965
Forged Eyebolts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 818.15-1969
Wing N u t s . Thumb S c r e w s . and Wing
..................................... 818.17-1968
Lock Washers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 827.1-1965
Trock Bolts ond Nuts
Miniature
Screws
Screw
Screws
Ploin Washers
........................................................
.......................................................
Beveled Washers
Generol Purpose Rectongulor Uniform S e c t i o n R e t a i n i n g R i n g s
........................
827.2-1965
827.4-1967
827.5-1969
BINDERS FOR HOLDING STANDARDS ARE AVAILABLE .
A COMPLETE LIST OF AMERICAN NATIONAL STANDARDS PUBLISHED BY THE AMERICAN SOCIETY
OF MECHANICAL ENGINEERS IS OBTAINABLE UPON REQUEST .
Copyright ASME International
Provided by IHS under license with ASME
No reproduction or networking permitted without license from IHS
Not for Resale
--`,,```,,,,````-`-`,,`,,`,`,,`---
Screws