Textbook of Engineering Drawing, Second Edition (repost)

CHAPTER 1:

1.1 Introduction

Drawing Instruments and

Accessories

Engineering drawing is a two dimensional representation of three dimensional objects. In general, it

provides necessary information about the shape, size, surface quality, material, manufacturing process,

etc., of the object. It is the graphic language from which a trained person can visualise objects.

Drawings prepared in one country may be utilised in any other country irrespective of the

language spoken. Hence, engineering drawing is called the universal language of engineers. Any

language to be communicative, should follow certain rules so that it conveys the same meaning to

every one. Similarly, drawing practice must follow certain rules, if it is to serve as a means of

communication. For this purpose, Bureau of Indian Standards (BIS) adapted the International

Standards on code of practice for drawing. The other foreign standards are: DIN of Germany, BS

of Britain and ANSI of America.

1.2 Role of Engineering Drawing

The ability to read drawing is the most important requirement of all technical people in any profession.

As compared to verbal or written description, this method is brief and more clear. Some of the

applications are : building drawing for civil engineers, machine drawing for mechanical engineers,

circuit diagrams for electrical and electronics engineers, computer graphics for one and all.

The subject in general is designed to impart the following skills.

1. Ability to read and prepare engineering drawings.

2. Ability to make free - hand sketching of objects.

3. Power to imagine, analyse and communicate, and

4. Capacity to understand other subjects:

1.3 Drawing Instrument and Aids

The Instruments and other aids used in draughting work are listed below:

1. Drawing board 2. Mini draughter 3. Instrument box

4. Set squares 5. Protractor 6. Set of scales

7. French curves 8. Drawing sheets 9. Pencils

10. Templates