Page:Sheet Metal Drafting.djvu/219

205 these lines. Upon these perpendiculars are set off the lengths of the correspondingly numbered extension lines in the half-profiles. Attention is called to the fact that points 1 and 5 have no altitudes, since they fall on the horizontal plane upon which the entire figure

rests. Straight lines connecting the points established upon these perpendiculars are the true lengths from which the pattern is developed.

The pattern is started by drawing a Horizontal line such as line 1-A of Fig. 294. With A as a center and a radius equal to the