Hi guys, I'm working on a 4pt roll bar for my 2nd gen. I'm building it out of 1 3/4" steel tubing.

I have access to a hydraulic pipe bender in the mechanic building of out shop ( I run the paint side.) I've been slowly teaching myself how to use it and I have a few questions.

One problem I'm noticing is a bit of a flat spot on the inside of the bend. It's doing the job but, cosmetically due to the nature of my work bugs the **** out of me. Is there a way to fix this, or make it less noticeable. I presume I could heat up the metal pre-bending it to help relax the bend? Or possibly heat the inside radius to red hot and then quickly quench/cool it causing it to shrink a bit? Would using a larger die and then switching to the correct, smaller one help?

Thanks.

 

maybe pack the pipe with sand?

 

With out a mandrel or draw bender its going to be hard to get a nice bend. Packing the pipe with sand does help but you have to weld on end caps. Another trick is to fill it with water and let it freeze.

 

Unless the dies are designed for smooth cage type bends you are probably won't have any luck with getting smooth bends. You don't want a bend radius that is less than 3x's the diameter of the tubing. If you have access to a larger radius die, try it.

I've known of a few people that have ruined plenty of tubing trying to use an exhaust bending machine to make a cage.

I've had one of these for over 20 years
JD Squared, Inc. - Model 3 Bender
The dies are designed to put a little load on the sides of the tubing so it stretches a bit instead of collapsing.

 

ive seen videos of packing the pipe with a water/sand mixture and duct taping the ends. made smooth bends even with a harbor freight pipe bender

 

I do have a mandrel, hand bender. Just don't have the correct dye and they want damn near $350+shipping for the correct dye.

Damn, I think I'm just going to by a hoop and fab the rest. Shame I got a really good deal on the steel and nothing else to use it on.

 

My company makes rotary draw benders (Rogue Fabrication, www.roguefab.com). You probably have a rotary draw bender. 99% of mandrel benders are electric or electric hydraulic. JD2 and the other common ones are all rotary draw benders. Do you have a plug that goes inside the tube? OR does the material wrap around a die?

 

if only I had $600 to spend on a bender....