Join Date: Sep 2007
Location: Baxter, Tennessee
The advantage is not having to use the heat. The bent pieces are the same with or without heat as far as strength. If you are using tool steel you can affect the spring like qualities by heat treating it properly so there is a difference in heat bending vs cold bending. However for most of what we do there isn't any advantage.
There is one difference and that is the type of heat source. When I was bending 1/2" rod with a Mapp gas torch you could only heat a small area. metal bends where it's hottest and resists bending where it isn't as hot. Consequently I got sort of a segmented curve. I can get a clean curve by heating the metal in my forge which heats up the whole piece to an even temperature.
By cold bending the metal is already at an even temperature. It just takes more physical effort. Bending 3/4" steel bar is pretty difficult unless you heat it.
Based on the above I wanted to cold bend to save fuel, I can bend it inside, and I don't accidentally burn myself.