Hydraulic Tube Bender

Cal Poly requires a senior design project to graduate and I wanted mine to be paramount. I had a tough time coming up with something that would tie together all I'd learned about machine design (my area of interest) without costing a fortune. So what did I do? Picked the most expensive thing I could come up with of course!

So here it is: a hydraulic tube bender. This puppy will be the cornerstone of my fab equipment. I will use it for making bumpers, sliders, crossmembers, suspension components, and of course roll cages.

This design is still a work in progress, so bear with me as I work through the design:

ABOVE Here you can see some of the basic design. The swingout will make tube loading and unloading a lot easier. The twin ram design will produce up to a 180 degree bend in a single stroke! You can bend as fast or as slow as you want: the machine will be capable of producing a 180 degree bend in under 35 seconds!

BELOW I am going to mount a potentiometer at the bottom of the arms to measure bend angle. After the machine is built and working, I will design a controller which will automatically shut of the machine at the desired bend angle. There will be a digital readout of the current angle and a readout for punching in the angle you want. You control the hydraulic rams with a manual valve, then when the desired angle is reached a solenoid valve will bypass flow. This should make for repeatable and accurate bends!

This machine is certainly not free. I've got big money into it already. I expect to spend as much as $2,000 before it is finished, not including uncountable manhours. But that's okay - a comparable production machine costs six Gs.

Now for some of the parts ($$$) going into this:

ABOVE This is a die set for a different type of bender which I will modify to work for mine. Each die is specific to the size tubing and bend radius you want. This particular one will do 1 3/4" O.D. tubing - the size I will use for most of my fab work. I would like to buy a few more sizes of these, but at over $350 this will have to hold me over for a while!

BELOW Doesn't look like $750, but hydraulic components are pricy. The big black beast is a hydraulic power unit, which comprises a 110VAC motor, hyfixed displacement pump, and 1.5 gal reservoir. This provides 2,000psi of pressure to drive the two 2.5" bore hydraulic cylinders. When it's done, this machine will produce an alloy-distorting 2,200ft-lb of torque! Insert your best Tim Allen grunt here gentlemen!!!

I will try to update this page as the design progresses, but at this point (late August) only the details of the swingout assembly are left. The next update probably wont be for another month or so, when I start cutting chips!


If you are a friend and would like to use this bender, please help me buy some more dies for it and I will be happy to lend it to you for your project! I am hoping to get some 1" and 1.5" dia tube dies and a 1" square tube die for future projects. They range in price from $150-300. If I buy them while I'm still in school, I can modify them for free using the machines on campus.

Tube Bender Design Is The Intellectual Property of Clinton Judd
Website And Images Copyright 2005 - Clinton Judd

Questions? cjudd@calpoly.edu