I just went to considerable trouble to describe a tube bender a friend built to a guy in the Ariel square 4 club and thought I would share it with you.
It was about like my 51 plunger sq.4. The bender was based on a car differential. One axle was locked and had a base bolted on and bolted to the floor. the top one mounted the tool wheel and an appropriate shoe to the side. The backplate flange is perfect for the job. The input shaft had a flywheel with starter ring driven by a starter pinion which was in an arbor with another flywheel/pinion driven by a large pulley/belt reduction. From the wall was a 1/2" rod with an appropriate size ball welded on that fit inside the tube freely at the point of the bending effort. You could about tell time with it. I suspect the big pulley was from a clothes dryer. I think he oiled the inside of the tube. Naturally the ball rod must be a bit longer than the tube stock.
He successfully bent 0.041" 1" dia. 4140 chrome moly and after tigging the frame together he heat treated it or normalized it in the American Airlines heat treating furnace.. 4140 is a bit more mallable than 4130 as I remember. He even made the wheel hubs, fork, handlebar, fuel tank, brake shoe backings, seat etc, just because he enjoyed the challenge. Threaded and cut the spokes too. It was a beautiful bike and wish I had thought to get pictures. I do think he used standard rear shock spring units. If my description lacks something, I will gladly clarify.
His name was Tom Terhune and lived in Collinsville OK. but as I am 76 and he was older than me, I imagine he is gone now. I remember he offered to make me a new back gear for my 9" South Bend on a RAM HEAD SHAPER !!!. I later lucked into an official one however. Don't EVER loosen a chuck with a bar without holding the back gear lever in position. I will never forget the crunch. He also replace a two stroke crank pin with a roller bearing pin. Quite a machinest. Keith Williams
It was about like my 51 plunger sq.4. The bender was based on a car differential. One axle was locked and had a base bolted on and bolted to the floor. the top one mounted the tool wheel and an appropriate shoe to the side. The backplate flange is perfect for the job. The input shaft had a flywheel with starter ring driven by a starter pinion which was in an arbor with another flywheel/pinion driven by a large pulley/belt reduction. From the wall was a 1/2" rod with an appropriate size ball welded on that fit inside the tube freely at the point of the bending effort. You could about tell time with it. I suspect the big pulley was from a clothes dryer. I think he oiled the inside of the tube. Naturally the ball rod must be a bit longer than the tube stock.
He successfully bent 0.041" 1" dia. 4140 chrome moly and after tigging the frame together he heat treated it or normalized it in the American Airlines heat treating furnace.. 4140 is a bit more mallable than 4130 as I remember. He even made the wheel hubs, fork, handlebar, fuel tank, brake shoe backings, seat etc, just because he enjoyed the challenge. Threaded and cut the spokes too. It was a beautiful bike and wish I had thought to get pictures. I do think he used standard rear shock spring units. If my description lacks something, I will gladly clarify.
His name was Tom Terhune and lived in Collinsville OK. but as I am 76 and he was older than me, I imagine he is gone now. I remember he offered to make me a new back gear for my 9" South Bend on a RAM HEAD SHAPER !!!. I later lucked into an official one however. Don't EVER loosen a chuck with a bar without holding the back gear lever in position. I will never forget the crunch. He also replace a two stroke crank pin with a roller bearing pin. Quite a machinest. Keith Williams