DIY Mandrel Bender

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Step 1: Tube Holding Blocks

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Step 2: Die

I got a gear weld on blank and cut the profile of the 5/8 tube in it , using a 5/8 ball end cutter.

Step 3:

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Step 4: Making a Cut Out for Clamp

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Step 5:

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Step 6:

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Step 7: Clamp Placement

Placed clamp to see how it fits now it's ready for welding

Step 8: Prep for Welding

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Step 9: Welded

I tig welded the clamp to the die using stainless steel filler rod

Step 10:

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Step 11: Back in Mill

I put the welded parts back into the milling machine indicated it straight ready for the cut with the ball nose cutter

Step 12: Blended in Ball Nose Cut

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Step 13: Machine Clamp

I screwed in the opposite side of the clamp to the die in the vice so I can hold it ,so I can machine it with the ball nose cutter

Step 14: Finished Machining Clamps and Die

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Step 15: Clamp

I tested the clamp on a piece of .625" inch round tube

Step 16: Mandrel

To make the mandrel I'm using a piece of M8 metric threaded rod , I put two stainless screws on the end of it getting them ready to weld together

Step 17: Mandrel

After welding together I forged it with a hammer to harden it.

Step 18: Grinding Mandrel to Size

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Step 19: Grinding Mandrel

To bring it to the right size and shape I put the end of the threaded rod into a drill then I sanded it on a disc sander,

Step 20:

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Step 21: Finished

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Step 22:

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Step 23:

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Step 24: Checking Fit of Mandrel

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Step 25: Tube Guide

I machined a tube guide from brass

Step 26: Tube Guide

I drilled holes to mount onto a plate

Step 27: Tube Guide Support

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Step 28: All Together

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Step 29: Crank Handle

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Step 30: Bottom of Crank Handle

I made a cut out for the tube clamp and a bored hole that locates the die

Step 31: Ready to Test

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Step 32:

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Step 33:

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Step 34: Worked Perfectly

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Step 35: Time to Make Some Parts

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Comments

[orange4boy]

Hi. Great, simple build. I have two questions.

1.Where did you get the "gear weld on blank"?

2. What wall thickness is the tube you are bending?

[Bonifabcustom]

Thanks , the blank i got from a place in Canada called princess auto and the wall thickness is 1/16”

[orange4boy]

A fellow Canajun! The Princess is a joy Thanks. That’s impressively thin wall!

Cheers!

[AbigailJ9]

Very nice indeed. mandrel benders can be crazy expensive ! The only thing I might suggest is using a hollow tube to connect to the mandrel instead of solid. The reason I suggest this is lubrication of the mandrel.

It was asked earlier how the rod would not get stuck in the bending of the tube. To the other person; the tube that holds the mandrel is anchored at the other end of the rod so the mandrel actually does not go anywhere past where it started. It's purpose is a sort of anti-crush mechanism so it sorta needs to have a certain place to be during the process or you could use one of those sexy multi ball type mandrels which actually go into the bend a little.

Lubrication of the mandrel is extremely important and the hollow tube would allow you to feed lubrication up and into the center of the mandrel then out a couple of small holes in the mandrel itself as you bend.

[Takdashark]

First off, amazing work! Ia little confused how the threaded rod mandre functions. I feel like I'm missing something. The rod would and get stuck in the part of draw through with it, so there's definitely something I missed or it magic!

[redchapman]

This is really cool, thanks for sharing! Can I borrow that ball nose cutter? Haha.

I was searching around online and found these guys: https://www.highpurity.com/custom-fabrication/mand...

Would you recommend them as well?

[rionela]

very good i was thinkung to make the die mobile or somthing like this ones

[ARJOON]

impressive work but that tig weld :S

[romulobc48]

[vincent7520]

Only on Instructables can you find people crazy enough to make a bender that I'm sure works even better than the manufactured ones !!!…

Thank you.

This is perfect.

Again thanks for posting.

[NovelUserName]

Very Impressive how well that works!