Engineering drawing is a graphic language used to communicate ideas and technical information. The document discusses the basics of engineering drawing, including definitions, applications, history, standards, tools, lettering, lines and line types. It emphasizes that engineering drawing is a key part of the design process, allowing engineers to solve problems by visually representing technical concepts and specifications. The learning objectives are to understand drawing fundamentals and develop skills in using instruments, lettering, and visual communication standards.

1. ADAMA SCIENCE AND TECHNOLOGY UNIVERSITY
SCHOOL OF MECHANICAL, CHEMICALAND MATERIAL ENGINEERING
DEPARTMENT OF MECHANICAL ENGINEERING
ENGINEERING DRAWING ; MEng1102
CHAPTER-1
INTRODUCTION TO ENGINEERING DRAWING
14/01/2024

2. CONTENTS
1. Introduction
2. Applications of Engineers Drawing
3. History Of Technical Drawing
4. Drawing Standards
5. Drawing Tools
6. Lettering
7. Lines And Their Types
8. Standards
Reference
1

3. Learning Objectives
 Able to define drawing and explain its advantage for technical
communication.
 Identify drawing instruments, able to use and properly handle them.
 Identify lettering standard and practice how to write.
 Explain the meaning of basic line types and their uses.
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4. 2
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15
19
1. INTRODUCTION

5. 1.1. Definitions: What is drawing?
A graphic representation of a real thing, an idea, or a proposed design
for later manufacturing or construction.
Graphics language uses as a way of communicating all necessary
information about an abstraction such as an idea or a concept.
This language is known as “drawing” or “drafting”
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6. 1. Try to write a description of this object.
2. Test someone attempt to make a sketch from your
description.
1.1.2. Effectiveness of Graphics Language
The word languages are inadequate for describing the size,
shape and features completely as well as concisely.
You can easily understand that …
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7. 1.1.3. Basic Elements of Engineering Drawing
Drawing as a Graphics language Word language
Line
types
Geometric
constructions
Lettering
Projection
methods
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8. Cont.…
Engineering drawing are made up of graphics language and word language.
Graphics language
Describe a shape
(mainly).
Word language
Describe size, location and
specification of the object.
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9. 1.1.4. Graphic Language
• Graphic language in “engineering application” use lines to
represent the surfaces, edges and contours of objects.
• A drawing can be done by freehand, or using instruments or
computer methods.
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10. A. Freehand drawing
• The lines are sketched without using instruments other than pencils
and erasers..
Example
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11. B. Instrument drawing
• Instruments are used to draw straight lines, circles, and curves
concisely and accurately. Thus, the drawings are usually made to
scale.
Example
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12. C. Computer drawing method
• The drawings are usually made by commercial software such as
AutoCAD, solid works and Catia etc.
Example
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13. 1.1.5. Types of Drawings
Artistic
Sketches
(Conceptual)
Diagrams
(Design)
Engineering Drawings
(Technical)
Drawing
Technical
Less technical More technical 10

14. 11
A. Technical versus Artistic Drawing
 Technical drawing must communicate the same message to every
user or reader of the drawing, whereas an artistic drawing is usually
interpreted differently by everyone who sees it.
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15. 11
B. Sketch versus Engineering Drawing
•Sketch: made without drawing tools... Just pencil and paper. Scale is
approximate, not accurate, but the sketch should still look like the
object.
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16.  Engineering Drawing: Made with drawing tools... Such as ruler, set
squares, protractor and compass. Scale should be accurate and the
drawing should be prepared carefully.
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17.  Engineers: are people who use technical means to solve problems.
They design products, systems, devices, and structures to improve
our living conditions.
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18. 1.1.6. Engineering Drawing In Design Process
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19. 11
15
19
1.2. APPLICATIONS OF
ENGINEERS DRAWING

20. 12

21. 13

22. 14

23. 15

24. 15

25. 15
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1.3. HISTORY OF TECHNICAL
DRAWING

26. 1.3. History of Drawing:
Drawing is one of the oldest forms of communication, dating back
even further than the verbal communication.
Historically drawing is started by the caveman.
He uses it for communication to lead his day to day life.
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27.  Egyptian hieroglyphics also play its own role for the development of
drawing.
 Leonardo da Vinci prepared mechanical drawings showing orthographic
views as we do now.
16
Cont.…

28. Then Industrial revolution is one of the milestones for the
development of drawing.
From time to time several rules and principles are developed to
utilize drawing as efficient as possible.
It is about 1749 in which the drawing with the current conventional
representations came into existence by Washington DC civil
engineers.
17
Cont.…

29. 19
1.4. DRAWING STANDARDS

30. 1.4.1. Drawing Sheet :
ISO standard size
c paper
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31. Cont.…
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32. 1.4.2. Drawing paper:
• The following elements to be noticed over the format of our drawing
paper:
• Border line: it is the peripheral heaviest lines which enclose all drawings.
• Title Block: It is a box where all information about the drawing such as
drawn by, checked by, date, scale, title of drawing, drawing number and
company name are specified.
• Guide line: is the lightest line used to guide the height of alphabets.
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33. 105
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34. 1.4.3. Drawing Scales
Scale: is a ratio between the linear dimension(Length and size) of a drawn
representation of an object and the actual object.
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35.  Designation of a scale consists of the word “SCALE” followed by the
indication of its ratio, as follows.
 SCALE 1:1 for full size
 SCALE X:1 (X > 1) for an enlargement scales
 SCALE 1:X (X > 1) for a reduction scales
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36. 1.5. DRAWING TOOLS
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37. 1.5.1. Drawing instruments:
 The preparation of technical drawing is
possible only through knowledge and skill in
the use of a variety of instruments.
 With the aid of knowledge, skill and practice
it is possible to bring perfection!
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38.  Pencils: 2H or HB for thick line
4H for thin line
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39.  DRAWING TOOLS
 T-Square
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(Set-Square)

40. Cont….
 Protractor
 Compass
 Divider
Adhesive Tape
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41. Cont….
• Sharpener
•
•
Circle Template Clean paper
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42. Drawing instruments:
• The preparation of technical drawing is possible
only through knowledge and skill in the use of a
variety instruments
• With the aid of knowledge and skill practice it is
possible to bring perfection!
• Sharpen the lead with a sandpaper.
• Adjust the needle and the lead so that the tip of the needle extends
slightly more than the lead.
needle
1.5.2. Preparing the Compass
lead
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43. Cont.….
Using the Compass
Start circle: Apply enough pressure to the needle, holding compass handle between thumb and
index fingers.
Complete circle: Revolve handle clockwise.
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44. 19
1.6. LETTERING

45. 1.6.1. Lettering
• Lettering is used on drawings to give dimensions and other relevant information needed to
fully describe the item. To communicate nongraphic information.
• The lettering must be neat and legible in order to be easily read and understood.
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46. 1.6.2. Lettering Standard
ANSI Standard This course
Use a single stroke Gothic
text style, either inclined or
vertical.
Use all capital letters.
Use 3 mm for most
text height.
Space between lines
of text is at least 1/3
of text height.
Use only a vertical Gothic
text style.
Use capital letters.
For letters in title block it is
recommend to use 5~8 mm text
height
Follows ANSI rule.
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47. Cont.….
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48. Cont.….
 A drawing will be improved by good lettering.
 However, a good drawing will look sloppy and unprofessional if the lettering
is poorly done.
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49. Example Placement of the text on drawing
Dimension & Notes
Notes Title Block
49
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50. 1.6.3. Basic Strokes
Straight Slanted Curved
Horizontal
1 1 2
3
Examples : Application of basic stroke
“I” letter “A” letter 1
2
3
4 5
6
“B” letter
50
41

51. Suggested Strokes Sequence
Straight and slanted line
letters
Curved line
letters
Curved line
letters &
Numerals
A. Upper-case letters & Numerals
51
42

52. The text’ s body height is about 2/3 the height of a capital
letter.
Suggested Strokes Sequence
B. Lower-case letters
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53. Stroke Sequence
I L T F
E H V X W
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54. O Q C G
5 7
45

55. j y f r
t
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56. c o a b
d p q e
u
s
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57. Leave the space between words equal to the space requires for writing
a letter “O”.
Example
1.6.4. Sentence Composition
ALL DIMENSIONS ARE IN
MILLIMETERS
O O O
OUNLESSOAND
OOTHERWISE SPECIFIED.
O
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58. 19
1.7. LINES AND THEIR TYPES

59.  To make your drawings easy to read, make the contrast between thick and
thin lines distinct.
 Thick lines(0.6 mm) should be twice the width of thin lines(0.3 mm).
1.7.1. LINES
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60. 49
1.7.2.

61. 50
Cont.….

62. 50

63. 50

64. Example : Line conventions in engineering drawing
51

65. Example : Line conventions in engineering drawing
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66. 19
1.8. STANDARDS

67. Standards
Definition
• Drawing standards are set of rules that govern how technical drawings are
represented.
• Drawing standards are used so that drawings convey the same meaning to
everyone who reads them.
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68. 54

69. Freehand
Sketching
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70. Straight Line
1. Hold the pencil naturally.
2. Spot the beginning and end points.
3. Swing the pencil back and forth between the points, barely
touching the paper until the direction is clearly established.
4. Draw the line firmly with a free and easy wrist-and-arm
motion
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71. Horizontal line Vertical line
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72. Nearly vertical
inclined line
Nearly horizontal
inclined line
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73. Small Circle
Method 1 : Starting with a square
1. Lightly sketching the square and marking the mid-points.
2. Draw light diagonals and mark the estimated radius.
3. Draw the circle through the eight points.
Step 1 Step 2 Step 3
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74. Method 2 : Starting with center line
Step 1 Step 2 Step 3
1. Lightly draw a center line.
2. Add light radial lines and mark the estimated radius.
3. Sketch the full circle.
Small Circle
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75. 1. Place the little finger (or pencil’ s tip) at the center as a pivot,
and set the pencil point at the radius-distance from the center.
2. Hold the hand in this position and rotate the paper.
Large Circle
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76. Arc
Method 1 : Starting with a square
Method 2 : Starting with a center line
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77. Quiz 1
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78. Summary
 Engineers are people who use technical means to solve problems.
 Demonstrate the line weights (thickness) and types (dashed or solid) of lines used in the
alphabet of lines that specify meaning in technical drawings.
 List the advantages of several different drawing instruments and the qualities that distinguish
them.
 Add legible and quick notes and dimensions to sketches using uppercase letters drawn by
hand.
 Lay out a sheet and fill in the information in the title block using standard letter shapes.
 Drawing standards are set of rules that govern how technical drawings are represented.

79. References
63
Cecil H. Jensen, Jay D. Helsel, and Dennis Short, Engineering Drawing and Design, Aug 17, 2007.
David, Allan Low, Manual of Machine Drawing and Design Mechanical Drawing, Jun 1, 2006.
https://www.slideshare.net/shameem.mist/engineering-drawing