Chapter 18
Working Drawings
Objectives
• Specify the contents, formatting, and
organization of engineering drawings
• Correctly prepare and interpret formal,
professional engineering drawings
Objectives (cont’d.)
• Discuss the primary differences between
drawings used in manufacturing projects
and those used in construction projects
• Effectively use scales to measure the
length of lines on a drawing
Introduction
• Manufacturing vs. construction drawings
• For fabrication or construction, drawings
must be presented in formal and
professional manner
– Must be interpreted in same way by everyone
– Engineering drawings considered legal
documents
– Reflect on quality of originator
Making It Formal
• Working drawings
– Show each part in all views necessary to
define features, sizes, tolerances, and
assembly method
– Have prescribed presentation form
– Should be organized, neat, and polished
Making It Formal (cont’d.)
FIGURE 18.03. The typical progression of the design of a part from a
conceptual hand sketch to a computer 3-D model to a formal working
drawing extracted from the model.
Sheet Sizes
FIGURE 18.04. Some
relative standard sheet
sizes, international and
US, used for formal
drawings.
The Formal Drawing Header in
Manufacturing Drawings
FIGURE 18.07. A typical
header for a formal
engineering drawing.
The Formal Drawing Header in
Manufacturing Drawings (cont’d.)
FIGURE 18.08. Inside the main
title block, the definitions of the
units, scale, and projection angle
help the reader to correctly interpret
the placement and orientation of the
views and the dimensions that are
shown on them.
FIGURE 18.09. The name of the
company, a statement of ownership
of the drawing contents, and
conditions of use are permanently
printed in the title block.
The Formal Drawing Header in
Manufacturing Drawings (cont’d.)
FIGURE 18.11. Signatures and
dates help establish the history
of development and leave a trail
of accountability.
The Drawing Area for Manufactured
Parts
• Geometry presentation
– Area showing object’s geometry should be
uncluttered
– Complicated objects require larger sheets or
multiple sheets
Object Views
• Use rule of orthogonal projection and
multiview representation
• Show as many visible edges in their true
length as possible
• General rule for presenting object
– Start with preferred configuration
– Add or subtract whatever views are necessary
to best show all of the geometry
Notes
• Special processing, handling, or assembly
procedures that are required but cannot be
specified by dimensions and tolerances or
by materials specifications
• Usually numbered and listed together
• Generally added whenever you want
something done to a part and you do not
know how else to specify it
Parts, Subassemblies, and
Assemblies
FIGURE 18.18. A set
of drawings for a project
is organized like the roots
of a tree. Individual parts
fit into subassemblies
or the main assembly.
Subassemblies fit into
higher subassemblies
or the main assembly.
Exploded Assembly Drawings
FIGURE 18.20.
An exploded
assembly drawing
including a bill of
materials for a
machine vise.
Outline Assembly Drawings
FIGURE 18.21.
An outline assembly
drawing of the
machine vise.
Sectioned Assembly Drawings
FIGURE 18.22. A
sectioned assembly
drawing of the
machine vise.
The Bill of Materials
• Text list of parts, subassemblies, and
subassembly parts
– Item number, corresponding part number, part
name, material from which part is made, and
number of times part is used in assembly
• Can appear on any assembly drawing or
as separate drawing or document
– Usually printed as a table on an assembly
drawing
Manufacturing Detail Drawings
FIGURE 18.23. Detail drawings for the machine vise.
Manufacturing Detail Drawings
(cont’d.)
FIGURE 18.23. Detail drawings for the machine vise. (continued)
Manufacturing Detail Drawings
(cont’d.)
FIGURE 18.23. Detail drawings for the machine vise. (continued)
Manufacturing Detail Drawings
(cont’d.)
FIGURE 18.23. Detail drawings for the machine vise. (continued)
More Examples of Manufacturing
Drawings
FIGURE 18.27. Working drawings for the computer disk drive spindle.
More Examples of Manufacturing
Drawings (cont’d.)
FIGURE 18.27. Working drawings for the computer disk drive spindle.
(continued)
More Examples of Manufacturing
Drawings (cont’d.)
FIGURE 18.27. Working drawings for the computer disk drive spindle.
(continued)
More Examples of Manufacturing
Drawings (cont’d.)
FIGURE 18.27. Working drawings for the computer disk drive spindle.
(continued)
More Examples of Manufacturing
Drawings (cont’d.)
FIGURE 18.27. Working drawings for the computer disk drive spindle.
(continued)
More Examples of Manufacturing
Drawings (cont’d.)
FIGURE 18.27. Working drawings for the computer disk drive spindle.
(continued)
Construction Drawings
• Why construction drawings are different
from manufacturing drawings
– Construction projects
•
•
•
•
Typically site-specific and large-scale
Often use the English system of units
Do not often use 3-D modeling
Are always built from the ground up
How Construction Drawings Are
Different from Manufacturing
Drawings
• Profile views vs. plan views vs. elevation
views
• Documentation
– Set of construction plans
– Specifications (specs)
How Construction Drawings Are
Different from Manufacturing
Drawings (cont’d.)
•
•
•
•
Bearings
Control points
Benchmarks
Site survey
– Existing features or structures
How Construction Drawings Are
Different from Manufacturing
Drawings (cont’d.)
• Construction projects too large and
expensive to build prototypes
– However, small-scale models sometimes used
• Unforeseeable problems likely
– Changes tracked on as-built drawings
Construction Plans
• Large number of drawings
– Cover sheet, site plan, elevation views,
foundation plan, floor plans, electrical plans,
roofing plans, sections, detail drawings, etc.
• Schedules of materials
• PE is legally responsible
Cover Sheet
FIGURE 18.32.
Cover sheet and
index for the
Baraga water
treatment plant
expansion project.
Site Plan
FIGURE 18.33.
Site plan for
Baraga water
treatment facility
showing existing
structure as well
as nearby
highway.
Elevation Views
FIGURE 18.34. Elevation view for overflow and drain portion of lagoon.
Foundation and Floor Plans
FIGURE 18.36.
First floor plan
for the Baraga
water treatment
facility.
Sections
FIGURE 18.38.
General section
through a house
showing room
layouts.
Detail Construction Drawings
FIGURE 18.41. Detail drawings showing how a door will be
installed in the Baraga water treatment facility.
Plan and Profile Drawings
FIGURE 18.42.
Plan and profile
drawing showing
the street and
corresponding
sewage pipe
for wastewater
system in Baraga.
Engineering Scales
• Virtually all engineering drawings made to
scale
• Ratios
– 2:1 means two inches on paper equals one
inch on object
• Scale indicates how close you are to object
Engineer’s Scale
FIGURE 18.45. Line to be
measured at a scale of 1"=200'
and a 20 Engineer’s scale.
FIGURE 18.46. Lines drawn
at a scale of 1"=40' and a 40
Engineer’s scale.
Metric Scale
FIGURE 18.47. Line drawn at
a scale of 1:2000 and a 1:20
Metric scale.
FIGURE 18.48. Lines drawn at
1:1 scale and a 1:100 Metric
scale.
Architect’s Scale
FIGURE 18.49. Line drawn at a scale of 1⁄4"=1'-0" and a 1⁄4" Architect’s scale.
FIGURE 18.50. Line drawn at a scale of 1⁄8"=1'-0" and a 1⁄8" Architect’s scale.
Considerations for 3-D Modeling
• Easy to generate:
– Different views
– Dimensions
– Headers
• Software cannot fully interpret functional
requirements
– E.g., acceptable dimension tolerances
Summary
• Learned that drawings must be able to
communicate desires of engineer or
designer
• Discussed formal drawing format with
proper views, sheet sizes, headers, and
drawing organization
• Discussed different types of scales and
their physical meaning