tubing bender

[williamsk1936@yahoo.com]

I just described a tube bender a friend built to a guy in the Ariel square 4 club and thought someone here might be interested too.

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

 

[HeadSmess]

nice concept for a mandrel bender change balls for different diameters.

was he driving through the crown wheel or the axle?

driving the axle makes sense cus then the crown has a 2:1 redux... but limits the radius somewhat, doesnt it?

mmmm, shaper. an old mate had a hand powered one. small, barely useful, but still handy. he sold it and didna tell me!

so you can imagine my reaction when i found out that the local highschool SCRAPPED all their metalwork equipment. not sell, SCRAP. throw away. bin model. melt. trash. 8 hercus lathes, a cruddy vertical mill, a fairly nice horizontal mill with blunt cutters, and... a 16" shaper!

oh. tooo dangerous or some such nonsense!

in australia, these sorts of machines are extremely hard to come by.

back gears? loosen chuck? oh my.

cam lock spindles and quick change boxes

interesting, talking to a fourth year fitter...they no longer touch on precicion grinding, wouldnt know what scraping is and consider it obsolete though its still more accurate than a surface grinder simply because a surface grinder can only grind as good as the finish on its own slides and what ground them and ITS slides and what ground them...plus operator error and wheel wear and other things that a person with a straightedge can do but a program cannot... so a shaper is like blacksmithing with a hammer and tongs or something.

wouldnt have a clue what a change gear is or how to calculate them for a bridgeport mill with indexing head to cut, say... the gears on a HT. or what cutters to use. etc etc. not even worth asking about bevel gears, lol.



learn more at home!

make less money!

just pressing buttons and loading code. woooweee.

 

[williamsk1936@yahoo.com]

the tubing bender for thinwall

It was a differential in which one axle housing mounted to a floor plate, planetary gears locked, and the other (top) brake backplate flange held the plate that carried the stationary shoe. The pinion was driven by a flywheel gear which was driven by a starter pinion connected to another flywheel driven by another starter pinion connected to a big clothes dryer pulley driven by a small pulley on the motor. He had a number of radii wheels of different diameters, each with a holding fixture to secure the tube. In his case all were for 1" dia. 0.041" chrome moly tubing. The ball was welded to a 1/2" rod secured to the wall and long enough to accomodate the tube to be bent. The ball was positioned at the point of begining to bend Tubes lubed inside and out. As he was a tool and die man at American Airlines, he had access to a heat-treating furnace where he normalized the frame after it was finished. You would have enjoyed watching the ram head I had my 53 Sunbeam S-8 block planed on. It was at an ancient oilfield machine shop. The table was about 3X6 ft and rolled back and forth under stationary clapper that swung on the backstroke. The table progressed laterally with each return stroke. Reversing was accomplished by a pair of 12-14" flat belt pulleys counter-rotating next to each other. The 2" flat belt from an overhead shaft was shuttled from one to the other with a rosin squawk that made my hair stand on end. The machinest looked to be in his 80's, or about as old as the machine. Did an amazing good job. The Sunbeam block was scalloped from bolt tension and was impossible to keep sealed. I made a 1/16" solid copper gasket for it and annealed the crap out of it. Helicoiled the block, inserted connecting rod studs, and I swear it looked like the gasket oozed a bit when I torqued it down. NO MORE LEAKS. Subsequently I sold it to a guy that over reved and stuck a valve head edgewise in the piston and ruined the seat. I bought it back. I had the head repaired by the first Heliarc process, a dry box purged with nitrogen.. A gunsmith friend made a flycutter and inserted a Stellite valve seat. Replaced the valves with Studibaker exhausts and Case tractor intakes with stems chopped and notched to fit. Worked great.