DIY Mandrel Bender


Introduction: DIY Mandrel Bender

About: I'm an inventor , machinist , welder .


Step 1: Tube Holding Blocks


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:


Step 4: Making a Cut Out for Clamp


Step 5:


Step 6:


Step 7: Clamp Placement

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

Step 8: Prep for Welding


Step 9: Welded

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

Step 10:


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


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


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


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:


Step 21: Finished


Step 22:


Step 23:


Step 24: Checking Fit of Mandrel


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


Step 28: All Together


Step 29: Crank Handle


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


Step 32:


Step 33:


Step 34: Worked Perfectly


Step 35: Time to Make Some Parts




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    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!

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


    impressive work but that tig weld :S

    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.

    Very Impressive how well that works!