AutoCAD 2D-I
Module 1: Introduction to Drawing Tools
PREPARED BY
IAT Curriculum Unit
January 2011
© Institute of Applied Technology, 2011
ATM1020 – AutoCAD 2D-I
Module 1: Introduction to Drawing Tools
Module Objectives After the completion of this module, the student will be able to:
Identify and describe the use of engineering drawing equipment
Recognise different methods of laying out engineering drawing papers.
Demonstrate the use of scales.
Produce a simple drawing paper layout including border and title block.
Module Contents
1 Introduction ...................................................................................2
2 Drawing instruments......................................................................2
2.1 Drawing Boards ........................................................................... 2 2.2 T-Square .................................................................................... 3 2.3 Set Square.................................................................................. 3 2.4 Pairs of Compasses ...................................................................... 3 2.5 Protractor ................................................................................... 3 2.6 Ruler.......................................................................................... 4 2.7 Drawing pencils ........................................................................... 4 2.6 Eraser ........................................................................................ 4 2.8 Circle template ............................................................................ 4
3 Drawing Paper ...............................................................................5
3.1 Sizes of the drawing paper............................................................ 5 3.2 Scales ........................................................................................ 5 3.3 Layout of the drawing paper.......................................................... 5 3.4 Line type .................................................................................... 6
4 Technique of Lettering ...................................................................7
5 Activities ........................................................................................8
5.1 Class Activities ............................................................................ 8 5.2 Homework .................................................................................. 8
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2 Module 1: Introduction to drawing tools
1 Introduction
Technical drawing is the study of the
procedures, tools, supplies, skills and
techniques used to record and communicate
the shape and size of a product. Every product
we have today (e.g. cars, houses, machines,
etc…), began as an "idea" in some person's
head. Before these "ideas" became products,
they had to be drawn on paper so as to show
what the idea looks like from different
directions, Fig.1.1.
Fig.1.1: Burj Al Arab- Dubai
2 Drawing instruments
To prepare a drawing, one can use manual
drafting instruments as shown in Fig.1.2, or
computer-aided drafting (CAD).
If the drawing is made without either manual
instruments or CAD, it is called a freehand
sketch.
The following instruments are essential and
should be available to produce a good quality
technical drawing.
Fig. 1.2: Manual Instruments.
2.1 Drawing Boards
Drawing Boards can range from simple boards,
like the one shown in Fig.1.3, to complicated
drawing machines that would be used in
engineering drawing office. The surface of the
board should be dusted and smooth.
Fig. 1.3: Drawing Board
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Module 1: Introduction to drawing tools 3
2.2 T-Square
2.3 Set Square
2.4 Pairs of Compasses
2.5 Protractor
T- Square is composed of a long strip, called
the blade; it is placed on the drawing board
and provides a constant horizontal edge. The
T-square is shown in Fig.1.4.
Fig. 1.4:T-Square
Set Squares are best made from transparent
plastic. The two standard set squares that are
commonly used are 30/60 and 45/45 degrees
triangles as shown in Fig 1.5.
45/45 triangle 30/60 triangle
Fig. 1.5:Set Square
There are basically two types of compasses
1. Pencil compasses which are used to draw
circles. Circles up to 300 mm diameter are
drawn using a large radius compass.
2. Spring bow compass which is used to
draw circles of 50 mm diameter or less.
(Fig.1.6). Fig. 1.6:Compasses
Protractors measure angles other than those
obtained by the set squares and found in
half circle or full circle types, Fig. 1.7.
Fig.1.7: Protractors
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4 Module 1: Introduction to drawing tools
2.6 Ruler
2.7 Drawing pencils
2.6 Eraser
2.8 Circle template
A 300 mm ruler with one edge marked in
centimeters and millimeters is necessary,
Fig.1.8. In a fully equipped drawing machine,
horizontal and vertical rulers with graduations in
mm or inches are attached to the drafting head.
Fig.1.8: Ruler
Pencils have nine grads of hardness from H
to 9H and seven grades of softness from B
to 7B as shown in Fig. 1.9.
Fig.1.9: Pencil lead grades.
Erasers are available in different hardness and
are used to erase pencil work. The common
eraser used is a block-shaped vinyl eraser.
(Fig.1.10). Fig.1.10: Eraser
Circle templates are useful for drawing small
circles quickly and to join lines with a radius, A
circle template is shown in Fig.1.11.
Fig.1.11: Circle template
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3 Drawing Paper
3.1 Sizes of the drawing paper
3.2 Scales
In order to produce drawing showing components in detail or as plans it is often
necessary to use a scale. This can increase the size of the drawing in comparison
to the real size of the component.
Some of the recommended scales are listed below:
Enlargements scales: 2:1 20:1 50:1 10:1
Full (same) size: 1:1
Reduction scales: 1:2 1:10 1:20 1:100
3.3 Layout of the drawing paper
Drawing sheets of all sizes have standard layout. It is usual for each sheet to be
provided with a drawing frame a short distance from the edge of the paper as
shown in Fig.1.13.
Each drawing sheet has to be provided with a title block which represents the
general information source for a drawing. It is normally placed in the bottom and
at least contains the title of the drawing, the name of the draftsman, the scale,
and the date.
Drawing paper is available in ‘A’ series, ‘B’
series, and rolls of the International Organization
for standardization (ISO), but series ‘A’ is
preferred.
Paper sizes for series ‘A’ are based on the A0
size, which has an area of 1 square meter. An
A0 size sheet can be divided up evenly into the
various other sizes (A1, A2, A3, A4…) simply by
halving the sheet on the long side in each case.
As shown in Fig. 1.12.
Fig. 1.12: Paper Sizes
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6 Module 1: Introduction to drawing tools
200
265
330
15
15BORDER
NAME: TITLE: SECTION: DATE: SCALE
100
Drawing frame
Title block
Fig 1.13: Layout of the drawing paper.
3.4 Line type
Fig. 1.14 shows the types
of line which are
commonly used in
engineering drawings such
as visible lines, hidden
lines, center lines,
dimension lines, extension
lines, and leader lines.
Fig. 1.15 shows an
application for the use of
different types of lines.
Chain thin
Visible outlines
Dimension linesProjection linesLeader lineshatching
Hidden outlines
Circle centerlines
LINE Description Application
Continous thick
Continous thin
Dashed thin
Fig.1.14: Line types and their description
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Module 1: Introduction to drawing tools 7
70
OUTLINE(CONTINOUS THICK)
HIDDEN UOTLINES(DASHED LINE)
DIMENSTION LINE(CONTINOUS THIN)
CENTER LINE(CHAIN THIN)
130
20
10
30
15 20
50
1105
Fig 1.15: The use of different line types in engineering drawing.
4 Technique of Lettering
These guide lines can be used to make sure that all letters and numbers have the
same size. Always print using capital letters. All letters and numbers should touch
the top and bottom guide lines. Guide lines should be 5 mm apart as explained
earlier. An example for lettering technique is shown in Fig 1.17.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
Fig. 1.17: Printing numbers and letters.
Printing increase the information that is provided
on a drawing. Printing must be clear and neat so
that it is easy to read. Use guide lines 5 mm
apart as illustrated in Fig. 1.16.
5
Fig. 1.16: Guide lines for printing.
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5 Activities
5.1 Class Activities
Draw the objects shown below in full size using different drawing tools such as
compasses, set squares and tee square. Use an A3 sheet to create the drawing
with the same layout shown below.
? 100
R30
80
110R15
3040
50
80
R15
R35
R20
80
21
3 4
NAME: TITLE: SECTION: DATE: I.D.No.
5.2 Homework
Draw the objects shown below in full size using different drawing tools such as
compasses, set squares and tee square. Use an A4 sheet for each of the
following objects
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Module 1: Introduction to drawing tools 9
1.
45°
45°
R45
2.
50 20
120
30 60
201550
3.
1515
60°30
60
120
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10 Module 1: Introduction to drawing tools
Student notes
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