I threw this bender together in about an hour after the one I ordered on amazon was backordered. The bend radius is 3" The side plates are 4" radius made from 1/4" plate. The center was a couple of pieces of 1/2" oak I laminated together. The handle is obviously the weak link, and is going to be replaced with a piece of 1.25" pipe. That surely won't bend. It makes repeatable bends without kinking...which is what I needed. I bent 8 - 90* bends and 4-45* bends for a project I am working on.
Specs: 1/4" steel plate semi circles cut to an 8" radius, 1"oak laminate (for strength) "core" cut to a 6.25" radius. The oak was then sanded so it had a rounded profile with the edges brought down to 6". This dimples in the center of the tube to allow the bend to happen. Handle in this vid is only a 3/4" pipe from my scrap pile. At the "front" of the bender, a hoop of 1/8" strap is welded. The side plates are bolted on to allow loosening in case the tub gets jammed in the bender. The two halfs won't come apart due to the welds, but it allows for some movement.
What I would do differently: 1" or 1.25" pipe for the handle. Machine an aluminum block for the core. Longer handle. wider/longer foot pad. new 7018 rod instead of piece of crap 6013 from my basement.
I weigh 250, and with the handle at this length, it took all i had to start the bend. watch me bust my ass!
