The document provides an overview of drafting tools and techniques used to create technical drawings. It discusses the role of graphics in visualization, communication and documentation. It then lists common drafting tools like a drawing board, T-square, protractor, pencils, and a drafting machine. It also covers different dimensioning styles, scales used in drawings, orthographic and multi-view projections, and conventions for labeling points and views.

1. By
Ankit Saxena
Assistant Professor
Mechanical and Automation Engineering Department

5. The Role of Graphics
• Visualization
• Communication
• Documentation

16. Drawing board
A drawing board is
rectangular in shape
and is made of well
seasoned soft wood
such as oak or pine.

17. Drawing sheet

20. ADGITM,NEW DELHI

21. Drawing Sheet Holder

22. Set-squares – 45degree and 30degree
– 60degree

23. Large size compass

24. Protractor

25. French Curve

26. Drawing Pencils – H, 2H, HB

27. Grades of Pencils (Video)

28. Drafting Machine / Mini Drafter

38. 1. Chain Dimensioning:
Dimensions are arranged in a straight line.
2. Parallel Dimensioning:
All the dimensions are shown from a
common base line. The smaller dimension
is placed nearer the view.

39. 3. Combined Dimensioning:
Chain and parallel dimensioning used
simultaneously.
4. Progressive Dimensioning:
One datum or surface is selected
which reads as zero. All the
dimensions are referred to that point
or surface.

44. Scales
Introduction
A scale is defined as the ratio of the linear dimensions of element
of the object as represented in a drawing to the actual dimensions
of the same element of the object itself.
Types of the scales
 Drawing drawn of the same size as the objects, are called full-size
drawings and the scale used is known as full-size scale.
 It may not be always possible to prepare full size drawings .They
are, therefore, drawn proportionality smaller or larger.
 When drawings are drawn smaller than the actual size of the
object (as in case of building, bridge, large machines etc. ) the
scale used is said to be a reducing scale (1:5) .
 Drawing of small machine parts, mathematical instruments,
watches etc. are made larger than their real size. These are said to
be drawn on an enlarging scale (5:1).

45. Projections
Projections
Orthographic
Projection
Isometric
Projection
Oblique
Projection
Perspective
Projection
In these methods the object is represented by a
pictorial view as eyes see it. In these methods of
projection a three dimensional object is
represented on a projection plane by one view
only.
While in the orthographic
projection an object is
represented by two or three
views on the mutual
perpendicular projection planes.
Each projection view represents
two dimensions of an object. For
the complete description of the
three dimensional object at least
two or three views are required

46. Orthographic Projection
• When the projectors are parallel to each other and also perpendicular to
the plane, the projection is called orthographic projection.

58. CONVENTIONS USED
• Actual points, ends of lines, corners of solids
etc. in space – A,B,C, …..
• Top views – a, b, c, …..
• Front views – a’, b’, c’, …..
• Reference line – x y

59. Projection of Points
Sheet No. 1