While re-doing my 67 C50 school bus I need to add some duct work so the wife wouldn't get cold while riding. The bus had the side heat vents covered by cabinets. I needed to custom bend sheet metal. Being the frugal person I am (my wife says cheep), I needed a metal brake and didn't want to spend the big bucks to buy one. I found this:
http://www.ch601.org/tools/bendbrake/brakeplans.pdf
I did very little tweaking to fit my needs. I made it so I can remove it from my metal table and just use C clamps to hold it on. To do this I drilled the outside holes and tapped a 1/2 hole in the bottom plate then welded the bolts in place so I could grind the bottom smooth so it would sit flat (I used 1/2" not the 3/8" bolts). Then increased the size of the top hole so the "hold down" plate would fit. I did not use any bolts in the center of the bending area, but did use a little heavier steel on the 2 plates that sit on the table. I also welded the handle and the piano hinge.
The page says it cost about $75 to build. I spent a little more than that, but still around $100, and the brake works great. Anyone who is trying to build custom sheet metal parts or the ones that are "Kinda hard to find" will find this a great ad-on to the garage.
I wish I could say I came up with this but I have to thank
Dave Clay of Temple, Texas for this idea.