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1. INTRODUCTION
TO
ENGINEERING GRAPHICS

2. Drawing Instrument

3. Typical Drawing Equipment
Objectives in Drawing
1. Accuracy
2. Speed
3. Legibility
4. Neatness

4. Drawing Boards
The left edge and right edge of a
drawing board has a true straight
edge.
For right-handed people, the left-
hand edge of the board is called the
working edge because the T-square
head slides against it.
For left-handed people, the right-
hand edge of the board is called the
working edge because the T-square
head slides against it.
T-Squares
The T-square is made of a long strip
called the blade, fastened at right
angles to a shorter piece called the
head.

5. The drawing paper should be placed
close to the working edge of the
board to reduce any error resulting
from the bending of the blade of the
T-square.
The paper should also be placed
close enough to the upper edge of
the board to permit space at the
bottom of the sheet for using the
T-square.
Drafting tape is used to fasten the
drawing paper to the drawing board.

6. Drawing Pencils
High-quality drawing pencils should be used in technical drawing, never ordinary writing pencils.
Many makes of mechanical pencils are available together with refill leads in all grades. Choose
a mechanical pencil that feels comfortable in your hand.

7. HARD MEDIUM SOFT
9H 8H 7H 6H 5H 4H 3H 2H H F HB B 2B 3B 4B 5B 6B 7B
Hard leads are used where extreme
accuracy is required. Generally
these leads are used for construction
lines.
Medium leads are used for general
purpose line work in technical
drawing.
Soft leads are used for various kinds
of art work. These leads are too soft
to be useful in mechanical drafting.
Drawing Leads
The first consideration in the selection of a grade of lead is the type of line work required. For
light construction lines and guide lines for lettering use a hard lead. For all other line work, the
lines should be BLACK. The lead chosen should be soft enough to produce jet black lines but
hard enough not to smudge.

8. TASK LEAD GRADE LINE WEIGHT
CONSTRUCTION LINES 3H, 4H, 6H THIN, LIGHT
VISIBLE OBJECT LINES H, F, HB THICK, DARK
HIDDEN LINES 2H, H THIN, DARK
CENTER LINES 2H, H THIN, DARK
DIMENSION LINES 2H, H THIN, DARK
EXTENSION LINES 2H, H THIN, DARK
LEADER LINES 2H, H THIN, DARK
CUTTING PLANE LINES H, F, HB THICK, DARK
PHANTOM LINES 2H, H THIN, DARK
LETTERING H, F, HB THIN, DARK
Drawing Lead Applications

9. Drawing Horizontal and Vertical Lines
To draw a horizontal line, press the head of the
T-square against the working edge of the board
with your left hand. Lean the pencil in the
direction of the line at an angle of approximately
60º and draw the line from left to right. While
drawing the line, rotate the pencil to distribute
the wear uniformly on the lead to maintain a
symmetrical point.
To draw a vertical line, press the head of the T-square
against the working edge of the board with your left hand
and place a triangle against the blade of the T-square.
Lean the pencil in the direction of the line at an angle of
approximately 60º and draw the line upward, rotating the
pencil to distribute the wear uniformly on the lead to
maintain a symmetrical point.

10. Triangles
Most inclined lines are drawn at standard
angles using the 45º x 45º triangle and
the 30º x 60º triangle.
In addition to drawing angles of 90º, 45º,
30º, and 60º, triangles can be combined
to draw angles of 15º increments.

11. Scales
Scales are instruments used in making
technical drawings full size or at a given
reduction or enlargement.
Types of scales include metric scales,
engineers’ scales, decimal scales,
mechanical engineers’ scales, and
architects’ scales.
Scales are usually made of plastic or
boxwood and are either triangular of flat in
shape.

12. Giant Bow Sets
Giant bow sets contain various
combinations of instruments.
Giant Bow Compass
The giant (large) bow compass has a center
wheel and can be adjusted simply by opening or
closing the legs of the compass while turning the
center wheel.

13. Using a Giant Bow Compass
1. Set off the required radius on one of the center
lines.
2. Place the needle point at the exact intersection of
the center lines.
3. Adjust the compass to the required radius
4. Lean the compass in the direction that you are
going to draw the circle. Draw the circle in a
clockwise direction while rotating the handle
between the thumb and forefinger.

14. Sharpening the compass lead
A properly sharpened compass point is formed by
rubbing the lead on the sandpaper pad.
A properly sharpened
compass point consists of a
single elliptical face.
A properly adjusted compass
The needlepoint extends about
halfway into the paper when the
lead touches the paper.

15. Tee Square

16. Irregular / French Curves

17. SET SQUARES

18. DRAWING INSTRUMENTS
•Layout of a Drawing Sheet

19. Typical Sheet Sizes and Borders

20. A Series Formats
(mm)
A0 841 × 1189
A1 594 × 841
A2 420 × 594
A3 297 × 420
A4 210 × 297
A5 148 × 210
A6 105 × 148
A7 74 × 105
DRAWING INSTRUMENTS
2. Drawing Sheets

21. STANDARD SHEETS

22. TITLE BLOCK

23. ESSENTIAL REQUIREMENTS FOR TITLE BLOCK
1. NAME OF THE FIRM
2. TITLE OF THE DRAWING
3. MATERIAL TO BE USED
4. SYMBOL – FIRST ANGLE OR THIRD ANGLE
5. NUMBER OF SHEETS PERTAINING TO DRAWING
6. DRAWN BY
7. CHECKED BY
8. APPROVED BY
9. DATE OF RELEASE
10. DRAWING NO.
11. SCALE
OTHER INFORMATIONS, IF REQUIRED
1. TYPE OF TREATMENT
2. FINISH/COATING
3. STOCK SIZE
4. NO. OFF

24. Engineering Drawing
Lettering

25. - Size (or text height)
- line thickness
- Shape
- Space between letters
- Space between words
Recommendation
Legibility
Legibility
Uniformity
Uniformity
Text’s style on the drawing
must have the following
2 properties
Examples
GOOD
Not uniform in
style.
Not uniform in
height.
Not uniformly
vertical.
Not uniform in
thickness of
stroke.
Inappropriate
space
between letters

26. Style (this course)
Gothic vertical style.
Begin the sentence, phrase or word with a capital letter.
Text height 2~3 mm.
Space between lines of text is about of text height.
Height of the lower-case letter is about 2/3 of that of a
capital letter.

27. Basic Strokes
Straight Slanted Curved
Horizontal
1 1 2
3
“I” letter “A” letter
1
2
3
4 5
6
“B” letter
Examples

29. Leave the space between words equal to the space
requires for writing a letter “O”.
Example
Sentence Composition
ALL DIMENSIONS ARE IN
MILLIMETERS
O O O
O UNLESS
OTHERWISE SPECIFIED.
O

30. Engineering Drawing
Line Types

31. Basic Line Types &Application
Continuous
Dash
Chain
Style
Thickness Thick Thin 1. Dimension line
2. Extension line
3. Leader line
Center line
Hidden line
Visible line
represent features that can be seen in the
current view.
represent features that can not be seen in the current vi
represents symmetry, path of motion, centers of circles,
indicate the sizes and location of
features.
1. Visible
line
3. Hidden line
4. Center line
2. Dimension
line
Extension
line
Leader line

32. Basic Line Types An Example

33. Basic Line Types