Here’s a simple bending jig I’ve come across by David W. Wilson:
David W. Wilson’s Bending Jig
Bending Jig Parts
A thick steel plate and large bolts will handle heavier bending. However, a plywood base may be used for lighter bends. The steel plate base is easily assembled if the holes are threaded. But bolts and nuts will also work if held top and bottom through drilled holes in the plate. Various sized sockets from a socket wrench set adjust the radius of the bend. A metal strap may be used to hold the socket in place, and to help keep the bolts from twisting. Smooth bolts and sockets are preferable to threaded rods for the threads will damage the work piece. This type of jig can be held in a vise, or bolted to a work table. A large flat surface around it can help keep the bends flat.
The distance for the work piece between the bolts and/or socket should be snug to keep it from slipping. Several holes drilled into the base at various distances facilitate making numerous radius bends.
“S” type bends are easily bent with this jig. A long rod will help give leverage for several S’s. They may be bent by: 1. Inserting the end of the rod and bending the top part of the “S” 2. Work this bend back through the jig reversed, then bend the bottom of the “S”. Cut hook from section of rod, repeat. Scrolls are also easily bent by gradually working the work piece around a bolt or socket. For repeated work, it’s best to match it to a master shape.