Dimensioning

Abstract

All mechanical drawings that are used for production must contain dimensions so that the exact shape and size of the component or assembly are fully specified. The amount of information required depends mainly on the shape of the components. A very simple item such as a spacing piece in an assembly may not need a drawing of any kind. Its shape may be that of a rectangular solid cut from a flat bar, and the only dimensions necessary are length, width and thickness. If it is of cylindrical form, length and diameter are needed, and if it is tubular, the internal and external diameters and the length need to be drawn.