Boundy8e ppt ch01

Chapter One
Introductory and Standards
Information

Copyright © 2012 McGraw-Hill Australia Pty Ltd
PPTs t/a Engineering Drawing 8e by Boundy

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Purpose
This chapter provides an overview of how
to:
select a range of instruments suitable for drafting
understand the use of letters, numerals,
abbreviations and line types
choose drawing layouts, paper size and scales


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Select a range of instruments
suitable for drafting
 The advent of CAD (computer-aided
drafting) has not diminished the need for a
range of quality equipment to produce a
commercial standard of drafting/sketching
required in industry.


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Essential items include:




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Pencils (clutch and/or wood – cased)
Scale rule
Eraser and erasing shield
Drawing set
French curves
Circle and ellipse template
Adhesive tape
Fig 1.6


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 1.2 Drawing instruments
pp.4–6 (Boundy, A.W., 2012) illustrates the
essential drafting items; however, always
consult your teacher/instructor for advice on
the range and quality required to meet your
particular learning needs.


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Understand the use of letters,
numerals, abbreviations and line
types
1.3 Letters and numerals
p.8 (Boundy, A.W., 2012)
 The basic form for letters and numbers are
demonstrated in Figure 1.12, p.7.
 The height (h) of characters pertaining to particular
sheet sizes is stated in Table 1.2, p.8.
 Characters should be spaced twice the letter line
thickness or 1mm, whichever is greatest.


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Figure 1.12

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types
General rules for character usage:
 Use upper case letters (except for standards, e.g.
kg)
 Only use one style of character per drawing
 Use vertical characters for titles, drawing and
reference numbers
 Avoid underlining
 Characters should be kept clear of lines unless
essential to drawing.


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types
1.4 Types of line
 The types of line which are commonly used in
engineering drawings are illustrated in Table 1.3.,
p.9.
 Generally, thick dark lines apply to outlines (so
they stand out) and the rest (e.g. dimension,
hidden, short break etc.) are thin light lines with
some exceptions combining both thick and thin
(e.g. cutting plane).


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types
 The usage of line types is illustrated in Figure 1.14,
p.10.
 Table 1.4, p11 groups specific line type
thicknesses per metric sheet size in reference to
Table 1.3. (e.g. Type A continuous line {table 1.3}
is 0.7 thick for A0, B1 {table 1.4} sheet size.)


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Choose drawing layouts, paper size
and scales
1.6 Scales, p.10
 Scale – a ratio of drawn size to actual size.
 Ratio chosen should still allow easy interpretation
of drawing information.
 AS1100.101 – 1992 identifies scale ratios used in
Engineering and architectural drawings (e.g. shown
in Boundy, 2012: p.10).
 Scale used should be recorded near or in the title
block.
 A note ‘not to scale’ or ‘NTS’ indicates drawing is
not scaled.

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and scales
1.7 Sizes of drawing paper
 Based on A0 size as recommended by Standards
Australia.
 A ratio of 1 : 2 exists between the various A size
papers (see Figure 1.15 on next slide).
 The B series sheet sizes are intermediate sheet
sizes between the A series (ref. Figure 1.15 (b),
p.12).
 Drawing sheets can also be cut from standard rolls
(860mm and 610mm) to suit individual drawings.

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Fig 1.15 (c)
Fig 1.15 (a)


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and scales
1.8 Layouts of drawing sheets
pp.11–15
 AS1100.101 clause 2.5 identifies standard drawing
sheet layouts for all sheet sizes.
 Figures 1.16 and 1.17 p.13 (Boundy, 2012) show
typical layouts of A1 and A2 sheets.
 Sheet size designation will preferably be indicated
at the right-hand bottom corner of drawing frame.


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and scales
Drawing layouts should include:
 system of projection (1st or 3rd angle)
 drawing units, i.e. ‘all dimensions in millimetres’
 the drawing standard followed, i.e. AS1100
 drawings prepared for microfilming should indicate
the drawing frame dimensions or a graduated line
at least 150mm long.


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and scales
 Information relating to layouts are normally
recorded in or near the title block at the bottom
right – hand corner of the drawing frame (Figure
1.18, p.14 in Boundy illustrates examples).
 Drawing frames are spaced in from the edge of a
sheet, Figure 1.15(d) and Table 1.5 (Boundy,
2012) identify necessary detail.


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and scales
 Material or parts lists attached to title blocks are
included when a sheet contains several parts or an
assembly is shown and include information such as
part number, name, quantity, material, drawing
reference number, etc.
 Material or parts list may be placed on a separate
sheet when the list of parts is extensive or if its
more convenient to do so.


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and scales
 When changes occur on a drawing they should be
recorded on a revision table normally located at the
top right hand corner of the drawing frame.
 To assist in locating features on a drawing, zones
are located inside the drawing frame; horizontal
zones are designated by capital letters, while
vertical zones are numerical.
 Table 1.6, p.15 (Boundy, 2012) detail the number
of zones and widths of margins per sheet size.


1-18

Summary
To draw effectively you need appropriate resources,
follow standard forms of representation, such as line
types, understand the use of scaling as relating to
sheet size and record relevant information pertaining
to the drawing effectively.


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Boundy8e ppt ch01

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