1. Engineering Drawing
P.D.Kahanadge

2. Learning content, Introduction to Manufacturing Drawing
Lettering and Dimensioning
Conics (Parabola, Ellipse and Hyperbola)
Loci (Cycloids, Trochoids, Spirals, Involutes, Helices)
Lines and Planes (True lengths, Inclinations, Traces, Intersections)
Auxiliary projection methods and Method of revolution
Surfaces and Solids
Interpenetration curves
Developments
Isometric Views
Interpretation of Manufacturing Drawings
Limits, Fits and Tolerances
Surface Roughness and Machining Allowances
Sectional Views
Common methods of fastening
Orthographic views of assembled machine components
Drawing orthographic views from given exploded views
Components given scattered to draw orthographic views of assembly with part list.
Further examples in assembly drawings of machine components
Introduction to computer aided drafting
3D modelling

3. INTRODUCTION
In this modern society, an engineer plays a vital role and he thinks of engineering solutions for problems in his mind and conveys them to others through the language of systematic lines.
This language of systematic lines is called engineering drawing.
Therefore, an engineer must have knowledge of this language to project his ideas correctly on the paper and then execute the job efficiently and effectively with the help of this drawing.

4. Definition
Simply drawing can be defined as the art of representation of an object by systematic lines and shapes on a paper.
Drawing can be classified into two groups
Artistic drawing (Free hand or Model drawing)
Engineering drawing (Instrument drawing)

5. Artistic drawing (Free hand or Model drawing)
The art of representation of an object such as painting, cinema slide, advertisement boards, etc. by the artist by his imagination or by keeping the object before him is known as 'artistic drawing.

6. Engineering drawing (Instrument drawing)
The art of representation of engineering objects such as buildings, roads, machines, etc. on a paper is called engineering drawing.

7. Engineering Drawing also classified as following
01) Geometrical drawing
(i) Plane geometrical drawing
(ii) Solid geometrical drawing
02) Mechanical engineering drawing
03) Civil engineering drawing
04) Electrical & Electronic engineering drawing, etc.

8. Geometrical drawing
The art of representation of geometrical objects such as rectangle, square, cube, cone, cylinder, sphere, etc. on a paper is called geometrical drawing
There are two sections of geometric drawing
Plane geometrical drawing
Solid geometrical drawing

9. Plane geometrical drawing
The art of representation of objects having two dimensions I.e. length and breadth such as square, rectangle, triangle, etc. on a paper is called plane geometrical drawing.
Solid geometrical drawing
The art of representation of objects having three dimensions i.e. length, breadth and thickness such as cube, prism, cylinder, sphere, etc. on a paper is called solid geometrical drawing.
It is also called descriptive or practical solid geormetrical drawing.

10. Mechanical engineering drawing
The art of representation of mechanical engineering objects such as machines, machine parts, etc. on a paper is called mechanical engineering drawing

11. Civil engineering drawing
The art of representation of civil engineering objects such as roads, buildings, bridges, dams, etc. on a paper is called civil engineering drawing

12. Electrical & Electronic engineering drawing
The art of representation of electrical objects such as motors, generators, transformers, poles, towers, wiring diagrams, etc. on a paper is called electrical engineering drawing
The art of representation of electronic circuits of TV, V.C.R, calculators, computers, etc. on a paper is called electronic engineering drawing.

13. Drawing instruments and materials
Drawing board
T-Square
Set-square (30-60 deg triangle, 45 deg triangle)
Instrument box
Scales
Pencil and sand paper block
Protractor
Clinograph
Eraser

14. Drawing pins or Cello-tape
Irregular or French curves
Duster or handkerchief.
Drawing ink
Tracing paper and tracing cloth
Drawing paper
Sketch - book

15. Drawing board
A drawing board (also drawing table, drafting table or architect's table) is a kind of desk which can be used for any kind of drawing or writing on a large sheet of paper.

16. The standard size of drawing boards according to
Indian Standards Institution (I.S.I)
S.No
Designation
Size in mm
Length x Width x Thickness
To be used with sheet sizes 01 D0
1500 x 1000 x 25 A0 02 D1
1000 x 700 x 25 A1 03 D2
700 x 500 x 15 A2 04 D3
500 x 350 x 15 A3

17. Uses of Drawing board
The flat surface of the drawing board is used to hold the drawing paper while the drawing is being made.
The ebony strip of the board is used as a guide for the stock of the T-square

18. T -square
A T-square is a technical drawing instrument used by draft man primarily as a guide for drawing horizontal lines on a drafting table. It may also guide a triangle to draw vertical or diagonal lines.
Stock
Blade
Working edge

19. The standard size of drawing boards according to Indian Standards Institution (I.S.I)
S.No
Designation
Length and working edge in mm 01 T0
1500 ± 10 02 T1
1000 ± 10 03 T2
700 ± 10 04 T3
500 ± 10

20. Uses of T-square
The T-square is mainly used for drawing horizontal lines.
T-square is used as a base for drawing various angles with the help of set squares.

21. Set-squares
A set square or triangle is an object used in engineering and technical drawing, with the aim of providing a straightedge at a right angle or other particular planar angle to a baseline

22. Thirty-sixty degree (30°-60°) Forty five degree (45°)
Types of Set-squares:
Thirty-sixty degree (30°-60°)
Forty five degree (45°)
The 30°-60° set-square has three edges, one of which forms 90° and other edges forming angles of 30° and 60° with the other sides respectively
300
600
900

23. The 45° set-square is similar to the 30°-60° set-square, but its edges form an isosceles triangle in which two of the angles are of 45° each and other one's 90°
450
900

24. Uses of set-squares
The set-squares are used for drawing all straight lines except the horizontal lines which are usually drawn with T-square
The perpendicular lines or the lines at 30°, 60° and 90° to the horizontal can be drawn by using the set-squares
The perpendicular lines or the lines inclined at 45° and 90° to the horizontal can be drawn by using the set-squares
By using two set-squares, angles of 15°, 75° and 105° can be drawn

25. Instrument box
Large size compass (150mm long) with inter- changeable pencil and pen legs
Lengthening bar
Large size divider (150mm long)
Small bow compass (95 mm long)
Small ink bow compass (95mm long)
Small bow divider (95mm long)
Pin point
Ink point
Ruling pen or liner
Holder croquill
Lead case

26. Large size compass
This compass is used for drawing circles and arcs of circles of required sizes.

27. Uses of compass
The compass is used for drawing circles and arcs of circles of required sizes.
Steps of drawing a circle
Draw the center lines of the circle
Adjust the compass to the required radius using the scale
Place the needle at the center of the circle using the left hand
Draw the circle clockwise in one sweep, rolling the handle with the thumb and fore finger
If necessary, the pencil line can be brightened by making and additional turn

28. For very large circles, detach the pencil leg and insert the lengthening bar in its place.
Connect the detached part with the lengthening bar and finally draw the required circle

29. Drop Compass
Drop compass is used for drawing very small circles.
It has interchangeable lead and ink points.
This compass is particularly used by structure engineers in drawing rivet holes and heads

30. Small bow compass
The small bow compass is used to draw small circles and arcs of about 18 mm radius and if set, circle as small as about 1 mm radius can be drawn.
This compass can be either wheel type or side wheel type.
The use of small bow compass is similar to large compass

31. Large-size divider
The divider is used for dividing straight or curved lines into desired number of equal parts. This instrument also consists of two metal legs as in the compass, except for the fact that two steel points are provided instead of pencil point.

32. Uses of divider
(1) It is used to divide straight or curved lines into desired number of equal parts.
(2) It is used to transfer dimensions from one part to another part of the drawing.
(3) It is used to set-off given distances from the scale to the drawing

33. Small bow divider
The use of small bow divider is similar to large size divider.

34. Scales
The scale is a measuring stick, graduated with different divisions to represent the corresponding actual distances of ground according to some fixed proportion, thereby facilitating rapid between marking off distances on drawing.
All measurements of lengths or distances on a drawing are made with the scales.
The scale are either flat or triangular and the materials used in their construction may be wood, celluloid, metal, card-board, etc.

35. FULL SIZE SCALE
REDUCING
SCALES
ENLARGING SCALES
1 : 1
1 : 2
1 : 20
10 : 1
1 : 5
1 : 25
5: 1
1 : 10
1 : 50
2: 1
1 : 100

36. Uses of Scales
(1) It is used to prepare reduced or enlarged size drawings.
(2) It is used to set off dimensions.
(3) It is used to measure distances directly.

37. Ruling pen or liner
The ruling pen or liner is used for drawing straight lines in ink.
It consists of steel nib fitted to an ivory or metal holder.

38. Pencil
A pencil is a writing implements or art medium usually constructed of a narrow, solid pigment core inside a protective casing.
The case prevents the core from breaking, and also from marking the user’s hand during use.
The accuracy and appearance of the drawing depend on the quality of the drawing pencils.

39. GRADE OF PENCIL
HARDNESS 9H
Hardest
6H, 5H, 4H
Extremely hard 3H
Very hard 2H
Hard H
Moderately hard F
Firm HB
Medium B
Moderately soft and Black 2B
Soft and Black 3B
Very soft and Black
4B, 5B AND 6B
Very soft and Very Black 7B
Softest

41. Clinograph
The clinograph is a simple drawing instrument which is normally working together with a T-square and functions like a section liner or an adjustable set square

42. Protractor
In geometry, a protractor is a circular or semicircular tool for measuring an angle or a circle. The units of measurement utilized are usually degrees.
Protractors can be flat, circular and semicircular.

43. Eraser
Eraser is an article of stationary that is used for rubbing out pencil and also for pen mistakes. The most suitable eraser for pencil work is the soft white eraser.
Frequently used of eraser should be avoided.
Erased particles should be swept away using a duster.

44. Irregular or French curve
Use a French curve for drawing irregular or noncircular curves.
Some French curves have an ink riser as part of their design.
If your French curves do not have an ink riser, put one on with masking tape.

45. Drawing paper or Drawing sheets
There are different qualities of Drawing papers.
The quality of the paper to be used for drawing depends on the nature of the drawing.
The drawing paper should be uniform in thickness and of such a quality that the erasing effects should not be there.
In addition to that ink should not spread out.
One of the sides of the drawing paper is usually rough and the other side is smooth.
The smooth surface is the proper side for the drawing work.

46. It is recommended that drawing sheets according to ISO ‘A’ series
All ISO paper sizes have the same aspect ratio, one to the square root of 2, meaning that a document designed for any given size can be enlarged or reduced to any other size and will fit perfectly.
Given this ease of changing sizes, it is of course common to copy or print a given document on different sizes of paper, especially within a series, e.g. a drawing on A3 may be enlarged to A2 or reduced to A4

48. ISO A Drawing Sizes (mm)
Minimum frame border(mm) A5
148 X 210 15 A4
210 X 297 A3
297 X 420 A2
420 X 594 20 A1
594 X 841 A0
841 X 1189 25

49. Sketch book
A sketch book is used for recording sketches, data, notes and instructions relating to various jobs.

50. Drafting machine
A Drafting machine is a very useful tool in technical drawing, consisting of a pair of scales mounted at a right angle on an articulated protractor head that allows an angular rotation
The protractor head (two scales and protractor mechanism) is able to move freely across the surface of the drawing board, sliding on two guides directly or indirectly anchored to the drawing board.
These guides, which act separately, ensuring the movement of the set in the horizontal or vertical direction of the drawing board, respectively, and can be locked independently of each other.

52. Drawing exercises
Draw following angles using T-square and set squares.
150, 300, 450, 600, 750
Draw a straight line and bisect it.
Draw a straight line and trisect it.
Draw any angle and bisect it.
Draw any angle and trisect it.
Draw a straight line and divide it into 4 equal parts.
Draw a straight line and divide it into 7 equal parts.