I build a bending brake last night, similar to this one, except the hinge: http://www.biplaneforum.com/pdfs/brakeplans.pdf I used 2x2x1/4" steel angle for the main components, and 2 pieces of 3" long 1/8" wall 1" DOM tubing and a 3/4" bolt for each hinge. The hinges are centered on the 1/8" gap between the two pieces of angle iron. I welded everything together. It's 78" long, with a bending area of 66". The hinges are true, it swings freely without distortion. The small test pieces came out fine, including a 6" piece of 22 gauge stainless. So I put in a 40" long piece of .040" 2024-T3 to bend a stringer, and the brake doesn't even start to bend it. Increasing pressure just causes the movable angle iron to bend away from the fixed angle iron in the middle well over 1/2". I'm not sure how this is even possible, it's bending in the direction slightly between the "legs" of the angle where the angle should be most resistant to bending. The welds are good, the bolts haven't bent, and there doesn't seem to be any other problems. Has anyone ever had a problem like this, or even heard of one? This design has been made many times by many people, and they seem to work up to 8', mine is much shorter, so I can't understand why it's not even close to working here.