Figure 2-53. - Traingular development of a transition piece.

The DOUBLE-HEM EDGE (fig. 2-55) is used when added strength is needed and when a smooth edge is required inside as well as outside. The allowance for the double-hem edge is twice the width of the hem.

Figure 2-55. - Double-hem edge

A WIRE EDGE (fig. 2-56) is often specified in the plans, Objects, such as ice-cube trays, funnels, garbage pails, and other articles, formed from sheet metal are fabricated with wire edges to strengthen and

Figure 2-54. - Single-hem edge.

stiffen the jobs and to eliminate sharp edges, The