Author Topic: Recommended tube bender  (Read 2401 times)

Offline Mister_Fitz

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Recommended tube bender
« on: June 11, 2017, 12:58:52 PM »
I'm going to change the lower lengthwise tubes in my front engine dragster chassis. There is a small radius and small angel bend on each tube where the engine plate is located.
Which tube bender can you recommend? I should be both affordable and high quality as always...
I have seen an old video from Mark Williams where they are building a RED. At some point in the video they use a gas welder to heat the rubes and bend them into position. It was a bend with small angel. Is this a method still used? How is the tubes like this treatment?

Offline hotrod316

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Re: Recommended tube bender
« Reply #1 on: June 11, 2017, 03:05:49 PM »
we use pro tool bender, the bender is not bad, it's the dies that hurt????????
about 10 years ago we redid a mark Williams car that mark build (fed) yes he used a gas torch to heat the  tubes. we had many phone calls with then about that car.
steve m

Offline dreracecar

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Re: Recommended tube bender
« Reply #2 on: June 11, 2017, 03:09:05 PM »
Heat bending is the proper way to do this.  "ANY" comercially availble bender will crush the bend into the tube, whether it be a mandrel type or not for just a small bend area, its not as noticable when doing a longer bend.
 Its best to mark off a 6" area where the bend will be a heat the area with a "rosebud" tip, keeping a higher percentage of the heat to the inside of the bend because you want to compress the ID over stretching the OD.  The longer the sweep 6" vs 2" does not distrupt the material flow and less likely to kink the bend.
 It can be tricky, and is why a lot of shops build these "OIL DERRICK" frames instead of being more traditonal

 Pro tool, JD Square are junk for doing thin wall moly tubing because its a mandrel action without the mandrel and without it, the OD stretches and deforms the tubing and the bend is "EGG Shaped", do a bend with one of these type, cut the bend in the middle, rotate 180* and try and weld the 2 back together without using any rod
« Last Edit: June 11, 2017, 03:15:47 PM by dreracecar »

Offline rooman

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Re: Recommended tube bender
« Reply #3 on: June 12, 2017, 05:36:20 AM »
Bruce is right on the money on this one. When I was building Ernie Broughton's Comanche clone Don Long (who built the original) was adamant that heat bending was the only acceptable way to do it.

Roo
Yeah, I am from the south--any further south and I would have been a bloody penguin.

Offline Mister_Fitz

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Re: Recommended tube bender
« Reply #4 on: June 12, 2017, 12:01:47 PM »
It sounds like heat bending is the way to go.
I have never bent a tube with a gas torch before so every bit of tip or instruction of how to do this with a good result would be very much appreciated.
Would you bend the tube first then welding it to the frame. Or would you weld the first part of the tube to the frame then make the bend and after that weld the rest of the tube to the frame?

Offline ricardo1967

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Re: Recommended tube bender
« Reply #5 on: June 12, 2017, 12:58:14 PM »
Even heated, does it need to pack the tubes with sand to avoid crushing?

Offline dreracecar

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Re: Recommended tube bender
« Reply #6 on: June 12, 2017, 04:50:47 PM »
Even heated, does it need to pack the tubes with sand to avoid crushing?

 NO, thats why you heat up a 6" section and make it a gradual bend.

Offline dreracecar

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Re: Recommended tube bender
« Reply #7 on: June 12, 2017, 05:02:19 PM »
It sounds like heat bending is the way to go.
I have never bent a tube with a gas torch before so every bit of tip or instruction of how to do this with a good result would be very much appreciated.
Would you bend the tube first then welding it to the frame. Or would you weld the first part of the tube to the frame then make the bend and after that weld the rest of the tube to the frame?

 I do both if building a traditional torsion front half.  lock the frame down to the table so that the lower rails dont move and insert rail and spot tack. heat and bend til front part fits into a holding fixture and then do the oppiste side. the upper will have to be removable so to be able to fit the upper tube to the lower tube. When stacking the front tubes, where they come to the torsion tube, the width must be greater then the torsion tube so that there is at least 1/4 to 3/8" above and below the torsion tube so that the rails wrap 200* around it for proper welding and support and the cope where the upper and lower tube weld is much shorter instead of if the tubes where to meet the torsion tube the cope and weld would be much much longer

Offline ricardo1967

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Re: Recommended tube bender
« Reply #8 on: June 12, 2017, 05:47:24 PM »
Even heated, does it need to pack the tubes with sand to avoid crushing?

 NO, thats why you heat up a 6" section and make it a gradual bend.
Thanks Bruce!

Offline BK

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Re: Recommended tube bender
« Reply #9 on: June 13, 2017, 08:41:16 AM »
Are you talking just slight bends in the frame rails or all the bends like roll cage and the back of the seat?

Offline rooman

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Re: Recommended tube bender
« Reply #10 on: June 13, 2017, 09:42:48 AM »
^^^^^^^
Just the slight bend required at the mid plate etc. Anything like the cage and shoulder hoop requires an actual tube bender.

Roo
Yeah, I am from the south--any further south and I would have been a bloody penguin.

Offline Mister_Fitz

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Re: Recommended tube bender
« Reply #11 on: July 11, 2017, 12:42:09 PM »
Thanks for all the good advices.
Just one more question...  :)
Do I need a acetylene and oxygen gas welder or could I get away with a propane/butane (LPG) gas burner?

Offline dreracecar

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Re: Recommended tube bender
« Reply #12 on: July 12, 2017, 09:17:28 AM »
You will need a O/A unit and a rosebud tip torch to heat the tube 360* ,  you can use propane if you get a roofing torch, but you have to be real careful that you dont overheat the tubing because of the size of the flame it produces