Homemade tubing/pipe bender ?

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akwrencher

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I was wondering if anyone here has made a tubing/pipe bender suitable for exhaust pipes and the like. If so, would you be willing to post pics/tips? (Pops, I'd be shocked if you didn't have one :) )
 

Pops

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I just have this tube bender for 4130 tubing up to 7/8". I use it a lot making seats, tail surfaces, etc. Made by Imperial Eastman, Chicago, Ill. Works great. Dan
 

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bmcj

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Homemade tubing/pipe bender ? Wait... a homemade bender for tubes or a bender for homemade tubes? :gig:

(OK, OK... I know, but bad puns are how I unwind from a hard week at work.)
 

Brian Clayton

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I have a regular air/hydraulic bender, goes up to 4". On seamless tubing (chrome moly for example), the hard part is the dies. You can buy a set of dies for a particular size for about 150-300 bucks, depending on tubing diameter. You can build the rest yourself if you want, from a mechanical version, using a bottle jack or a power pack cylinder like mine. For exhaust tubing. Most production vehicle exhaust is done with a shoe and rollers, bending the pipe at the expense of wall collapse (3" tubing turns into 2 1/2" tubing in a bend). High quality bends (like headers) are mandrel bent, which uses external die and shoe, and a internal die to protect the tubing from wall collapse. A mandrel bender can be built at home (production ones are super high dollar), but it will take a lot of force from a hydraulic cylinder to bend the tube, not to mention they take up a lot of floor space. I build a lot a headers, but I just buy u bends and j bends and cut up what I need, welding it back together. I have looked at building a mandrel bender, but have not for two reasons. They take up lots of floor space, and complex bends require a great deal of planning and forethought. Its faster for me to "figure it out as I go".
Various materials have different outside diameters and bending qualities, so you have to know what you are planning to bend (and minimum radius) before you make/order dies or they will not work. Example, pipe and tubing od's are different, the dies are not interchangeable. Small diameter tubing (up to about 5/8 cm) can be bent in hand benders. A bender like Pops or a 3 wheel roller will bend most diameters under 1".

But yes. Easy way to build a bender is: Buy the die set, and use the various internet plans out there.

At one time, JD squared sold a manual bender for about 300.00. Nice bender frame, could be upgraded with hydraulics later and would bend up to 2 1/2 or 3" OD best I remember. Nice product for the money. Dies will eat you alive though. My bender cost about 5,000 10 years ago, and I probably have at least that much in different dies.

The problem with a bender that uses a die and floating shoes is wall collapse. Bents elect conduit okay (soft) but hard material is another game all together.
 

bmcj

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The old trick to bending tubing is to fill it with sand to keep it from collapsing. I have to wonder thow if the sharp grains of sand might cause scratches on the inside (as they are squeezed around the curve) that might become stress-risers?
 

Brian Clayton

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The old trick to bending tubing is to fill it with sand to keep it from collapsing. I have to wonder thow if the sharp grains of sand might cause scratches on the inside (as they are squeezed around the curve) that might become stress-risers?
Bend enough tubing like that, and you wont have the energy to care. :)
 

wizzardworks

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I built one years ago. The inside dies I made on a lathe. There is one for each OD of tubing. I made them for 7/8 thru 1-1/2 diameters. They drop onto a 600/1 ratio gearbox with a 2-3/4 diameter keyed output shaft.
There is a half round section about two inches long that goes around the outside of the tube and clamps it to the inside die. I bought the outside die from Parker Hanifin . It is a straight 2-1/2 " square by 12" long hardened bar
with one tube size in each face. The bar is slid up to butt the clamp backed up by a row of 3" diameter cam followers with 1-1/4" mounting studs and tapered roller bearings. The input shaft on the gearbox has an
automotive flex plate on a taper loc hub adapter. I just spin the flexplaste with my foot to power the bender. It was tested by just bending cold rolled steel shafting. If I use it again I will mount a starter motor to run
on the flex plate with the starter bendix locked. I also need a better scale of larger diameter to measure bend angle. The current one is a degree wheel for setting motorcycle timing.
wizzardworks
 

akwrencher

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Wow, thanks for all the good info guys. Looks like I will just stick to cutting and welding for now, but I will check out some of the info you have shared. I would like at least a basic setup someday, when I, too, have the floor space :)
 

kent Ashton

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These benders are not too hard to build from plans, but I agree with Brian that it's easier to buy the bends when making a header.
Got_trikes

Put "homemade pipe bender" in Google Images and you'll see lots of ideas.
 

Brian Clayton

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Wow, thanks for all the good info guys. Looks like I will just stick to cutting and welding for now, but I will check out some of the info you have shared. I would like at least a basic setup someday, when I, too, have the floor space :)
The trick to a tubing bender..... If its mechanical, it has to mounted to the floor or something substantial, if its powered, it bends against its own mass, so you can roll in the corner of the shop when you are not using it. Mine is mounted on a engine stand that I cut the top off of, rolls around wherever I need it, and plus I can put in the back of the truck, etc. Basic hydraulic stuff can be pretty cheap if you shop around.

I have thought about building a mandrel bender, to save me some money (increase profit :) ) but, it will have to wait for the new shop to get done..... I like wizzardworks bender.... I just have never made it a priority. I build more headers and exhaust than the average homebuilder will, and honestly its just as easy for me to buy u bends and j bends. The only way I really see a mandrel bender really being practical, is if you were building a lot of the exact same thing. The trick is to shop around for good deals on pre bent tubing, some companies eat you alive...esp stainless.
 

akwrencher

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I guess I don't really need one yet, and I definately don't have the room until I build the other half of my shop, but sure would be handy. It's a real pain ordering things here, at least as far as time is concerned. Makes simple projects take a long time :)
 

bmcj

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The old trick to bending tubing is to fill it with sand to keep it from collapsing. I have to wonder thow if the sharp grains of sand might cause scratches on the inside (as they are squeezed around the curve) that might become stress-risers?
Did I really type "thow"??? Must have been a really bad day!
 
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ekimneirbo

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I guess I don't really need one yet, and I definately don't have the room until I build the other half of my shop, but sure would be handy. It's a real pain ordering things here, at least as far as time is concerned. Makes simple projects take a long time :)
Building one from scratch might not be too bad if you have something to copy from, but by the time you work everything out, you still will have some money in it. The metal to make the dies is not something you can find easily because of the thickness needed. Then you have to machine the radius which is going to require special tooling or purchase dies from a manufacturer. You really are probably better off dedicating some time to working "overtime" and taking that money and buying a bender. Then it has more value if you ever want to sell it. Actual cost is what you paid minus what its worth after you have it a while, not just the initial cost. I recently bought a JD2 bender and its well made. The larger dies are expensive. One of the claims they make is that to prevent bends from wrinkling, you have to prevent the slight springback when you reset the bending die to complete your bend. They have a catch which prevents this springback....so if you build one, you may need to check out a pro bender. There are always ways to make benders that will handle smaller diameter tubing, but when you move up to exhaust pipe sizes, you need some power. I tried the pack it with sand method on a 1 7/8 exhaust pipe and
had no luck with making a small 30 degree bend. I heated the sand to make sure it was dry. welded an end on the pipe. Packed it with sand and then welded another end that could be tighted to compress the sand. Heated the pipe with a torch to help
ease the bending, and still had junk for the result. Maybe I didn't do it correctly, but I wasted a lot of time. So I decided to buy a bender that was versatile, easy to use, and has good resale value.
 
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ekimneirbo

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I built one years ago. The inside dies I made on a lathe. There is one for each OD of tubing. I made them for 7/8 thru 1-1/2 diameters. They drop onto a 600/1 ratio gearbox with a 2-3/4 diameter keyed output shaft.
There is a half round section about two inches long that goes around the outside of the tube and clamps it to the inside die. I bought the outside die from Parker Hanifin . It is a straight 2-1/2 " square by 12" long hardened bar
with one tube size in each face. The bar is slid up to butt the clamp backed up by a row of 3" diameter cam followers with 1-1/4" mounting studs and tapered roller bearings. The input shaft on the gearbox has an
automotive flex plate on a taper loc hub adapter. I just spin the flexplaste with my foot to power the bender. It was tested by just bending cold rolled steel shafting. If I use it again I will mount a starter motor to run
on the flex plate with the starter bendix locked. I
also need a better scale of larger diameter to measure bend angle. The current one is a degree wheel for setting motorcycle timing.
wizzardworks
You might look at the DC motors with speed controllers on Ebay. There are lots of them on Ebay and with a little searching you can find one with a control,maybe a reduction gear, and 110 Volt plug in. The one in the picture is 230 volt single phase 3/4 hp 20 to 1 gearbox for $144. They produce a lot of torque.
 

cheapracer

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The old trick to bending tubing is to fill it with sand to keep it from collapsing. I have to wonder thow if the sharp grains of sand might cause scratches on the inside (as they are squeezed around the curve) that might become stress-risers?
Have tried many times thru my life everytime a total failure, last time I even welded a threaded plunger that I screwed down to ultra-compact the sand, no good. I have also tried many other tricks such as springs inside the tube, it helps but complicated.

One thing I do want to try that I learned not so long ago is the use of one of the "Woods Metals" such as Cerrosafe. They melt at very low temps such as boiling water and popular with model builders for bending thin tubes.

Wood's metal - Wikipedia, the free encyclopedia



Otherwise I just use a standard old hydraulic pipe bender and get excellent results. you can improve the

One mistake is putting the 2 static dies too close together (the six position holes seen in this stock picture), seems logical but the actually work better further apart than what's usually recommended.

560372.jpg
 

proppastie

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I have used Cerrobend, for small stuff, much better than sand. Google for how to etc. Good luck
 
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