Page:Sheet Metal Drafting.djvu/15



1. Sheet Metal Drafting.—Sheet metal drafting is merely the application of the principles of ordinary mechanical drawing to objects which, for the purposes of drawing, lack thickness. By this is meant that the materials dealt with are usually in the form

of thin sheets and that their thickness is so slight that it may be represented by a line rather than by four lines and an included surface. The ordinary rules and conventions in use in mechanical drawing apply in general to sheet metal drafting. A knowledge of elementary arithmetic is also essential.