While I was working on a plant hanger design I decided to make a template to form the arc of the swing arms. I have a large collection of radius firms of differing dimension but I like to keep the tooling associated with any repeated project dedicated so I made a new form on a 7" radius jig.
I selected 1" square tube in 14 gauge since I have a large stock of this material. When I was building the studio I bought a bundle to get a good price and still have some left. I marked every inch with a presto pen dot to make about 14 segments. With the bandsaw I cut each mark down to the back wall then clamped the tube to the radius form so it conformed well. I tack welded the base of each kerf on the top and bottom sides making sure the tube stayed flat. Finally I welded the angle cross brace from end to end. One arm of the angle fits in the vise to hold the jig when in use.
I wouldn't say this is any better or more accurate than making a similar jig from solid bar in the forge and bending to the form but it is lighter, cheaper and can be done cold.
For many years before I took up blacksmithing I did woodworking as a hobby so I was familiar with kerf bending using a tablesaw. For anyone who wants to know more here is one link - http://stusshed.wordpress.com/2007/07/17/kerfing-bending-wood-on-the-tablesaw/