Basic Components of Engineering Graphics—the Code of Practice

Basic technical drawing is an essential component of all types of engineering graphics, nationally, and internationally. Within national and international trade, goods that are technical in nature almost always need to be accompanied by service diagrams or technical illustrations that express shapes, dimensions, and how components work whenever projections are assembled.

Examples of services could include consultancy work, design of communication towers, installation procedures for technological inventions, or even instructions on how to assemble simple devices.

Whenever information is exchanged, especially between people who don’t understand/use a common verbal language, technical drawings can give clarity, even when language barriers exist.

Before a unified approach was ever agreed on, IS:696: “Code of practice for general engineering drawing” was originally issued in 1955, and revised twice in 1960 and 1972 respectively.

Growing international cooperation and exportation of technology has necessitated the development of an internationally unified format that consists of components, rules, codes, conventions, and symbols that illustrate the language of technical drawing with engineering graphics.

Since the publication of the code of practice, many countries have made a lot of progress in standardizing the components of technical drawing with engineering graphics because of their adherence to the mutual agreement on the use of codes in and between countries.

The basic components of the code of practice used in technical drawing with engineering graphics include:

• List of drawing tools and items.

• Sizes/layout of drawing sheets.

• Folding of drawing sheets: how to fold drawing sheets.

• Assembly drawings.

• 2-D and 3-D views.

• Methods of dimensioning.

• Methods of sectioning.

• Cross-sectional views.

• Half-sections.

• Method for indicating surface texture.

• General principles for dimensioning.

• General principles of presentation: how to present drawings.

• Linear and angular boundaries/tolerances for engineering and technical drawings.

• Drawings for welding and metalwork.

• General scales used in drawing.

• Lines: thicknesses, spacing, and proportional dimensions.

• Lettering: dimensions and recommended sizes.