I thought I'd post a link that you may or may not be interested in. Reciently, I had another project that required bending sheet metal. I know there's something called a bending break for such a purposed, so I did some googling and this is what I came up with.

About halfway down this page the author of this article shows how to bend sheet metal with a home made wooden bending break.

http://www.hadfield.ca/Gear/stove.html

Hope this helps!

Jaxxx