Here are some better pics of the radius bender. Here it is, assembled, clamped on the welding table.

This is one end of the top "die" if you would. The notch in the end plates clears the 1 x 2 in the lower die and lets the centerline of the tube snuggle up to the edge of the 1 x 2.

A few of the notch with the bender assembled. The round tube is centered directly over the edge of the rectangular tube.

This is a cutoff from the tunnels we made. I clamped it in the bender with a C-Clamp. I'll do a little bending with this so you can see what can be done.

Bending the back edge up, around the top die. This was done by hand.

Bending the front edge down, around the rectangular tube for a sharp corner.

This is pretty cool. I'll get a lot of use out of this dude.

It will be easy to make additional top dies also. Black pipe of any diameter will make excellant dies to bend around.
Get out and build one of these things...
Thanks for looking.
Mark