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