Engineering Drawing Principles and Applications

Introduction

Drawing is a graphic language by which communication is accomplished through sketches (drawings). Drawings can be of various types. If compared with verbal or written description, drawings provide a far better idea about the shape, size and appearance of any object or situation or location, that too fairly quickly. From a manufacturing point of view, 2D and 3D drawings are very important and commonly used in engineering industry. Drawings are prepared manually or by using a computer. In 2D view (orthographic projection), one view is not enough to get all the details of the object. So it is necessary to draw the front view, top view, bottom view, right side view and left side view.

To be more useful, in particular from the manufacturing point of view, the sketch or drawing should include dimensions, manufacturing details, materials used, etc. Drawing equipment and instruments are needed to record information on drawing paper or any other suitable surface. Drawing, mainly consisting of straight lines, curves, circles and arcs, is prepared with certain instruments. The quality of the drawing mainly depends on the quality of the instruments, their adjustment, handling and care. Therefore, the equipment must be reliable and accurate, as the same will result in good quality drawing, which will further enhance a student's interest. The correct selection and use of pencils and drawing instruments should be taught throughout the course. Beginners certainly need guidance on the selection and purchase of the drawing instruments and equipment essential for drafting. The various instruments and other drafting equipment are described below.

List of Draughting Tools

The following is the list of draughting tools which every student must possess:

1. Drawing Board

2. Mini-Draughter

3. Small Instrument Box, containing the following:

• • Large Size Compass

• • Small Bow Compass

• • Large Size Divider

• • Small Bow Divider

4. Set-Squares

5. Set of Scales

6. Protractor

7. French Curves

8. Drawing Sheets

9. Drawing Pencils

10. Paper Fasteners

11. Pencil Sharpener

12. Sand Paper Pad

13. Eraser

14. Duster

Some of these have been explained in greater detail in the subsequent sections.

Drawing Board

A drawing board is usually made of well-seasoned soft wood. To prevent warping, narrow strips of wood are glued together.