The Official Tube Bending Thread

If you have a tube with a bend in it and you want to duplicate the bend, what is the best way to measure the radius of the bend on the original part? Is the industry standard spec for dies always CLR?

 

Yes.....when speaking "tube bender language" you always want to measure CLR (center line radius)

Here is a link to our library with a ton of "fun facts" that will make you life easier when bending tube.

http://www.bii1.com/library.php

 

Just bookmarked that link, thanks...

 

What kind notcher are you using on this cage? Notching on a bend like that can be pretty challenging. Looks like you have it mastered.

 

I sure wish i could have had access to a nice bender! I ended up going to a muffler shop to get this piece bent and now i have to deal with these corners!!
Damnit!!



Ian

 

Sorry, but you lost me. What part are you talking about?

 

Top corners have the indentation from the bender.

 

Oh OK......you had them bent with a HUTH or a "ram style" exhaust bender.

 

Yep!

 

Great link, some good info. Still not sure on the amount of force needed to make common bends in “cage size” tubing. Anybody got a WAG.


Hey Ian,


Nice work, the grill opening is very good. The “bar” looks like something I have seen before, what is it?


Later
Tork

 

Hey thanx tork! I bought the middle piece from a hamber and the description was " over rider bar", it used to be shaped kinda like the kaiser bar but i cut the ends off to fit some dummy lights which i reversed and also cut the ends and mounted lenses to use as turn signals.

 

For those of you that are involved with drag racing and haven't been to your first chassis inspection, NHRA uses a sonic wall tester. If the tube in question isn't the proper thickness or above, you will be sent home to repair your chassis. No exceptions.

 

Looks great though. Good job

 

a few words on tube bending, if any of you guys need exhaust tubing mandrel bent I can do that for you. I can do from 1 3/4 to 5 inch. It aint cheep but neither was the bender, three inch works well in custom body work. I'm not a vendor I'm just trying to help fellow hodders.. ( Atlanta area ) send me an PM with your needs.

 

Here is a piece of 1 5/8" (1.625") x .083" CM tubing that was bent 85 deg on a 4 1/2" CLR JD2 Model 3 die, this is the cut was made in the middle of the bend.
A: .096"
B: .076"
C: .079"
D: 1.490"
E: 1.647"

 

Thanks Kenneth - that's what I was looking for.

The tube kinda take's on a ( D ) shape.

I have been watching this for 15 years or so,

Back in the mid 90's - using a JD2 bender - then a JD3, I would see about a .040 to .050 differance in 1.625 x .083 4130N Tube with a 5.5 die.

These day's - I am getting similar results to yours.

I believe the material is not being made the same way as it was.

 

Yep, they don't make things like they used to that's for sure.

 

Shane, I had a question about bending some 1/2" chromemoly tubing for a parachute mount. Can you sand bend it with heat or is it to hard? Thanks Duane

 

I'll tell ya.....

I am not a sand bending expert by any means. I thought it was more or less a myth before getting on the HAMB. I have been dealing with tube and pipe benders forever and have just never come across the "sand bending" crowd.

I'm sure there is someone else on this board that would be more help on this question. Sorry.

 

Thanx BAILEIGH!! i rounded the hood corners, it flows better now i think.



Ian

 

In agree with you. Looks way better.

Nice work!

 

Some of that material coming out of China is pretty inconsistent. I have had a couple customers struggling with it. <!-- / message -->

 

I just bent this scrap piece of tubing on my Hossfeld bender and here is what I found. The tube is 2" x .120" HREW P & O material. The die set is a 6" CLR. I have a 36" stroke cylinder for doing 90° bends in one stroke that has a 2-1/2" bore. At the start of the bend (when the leverage is the lowest) my pressure gauge reads just at 500 PSI. As the cylinder extends, the pressure drops to a little over 400 PSI and then starts climbing as it approaches the 90° mark.



The area of the piston for a 2-1/2" cylinder is 4.909 Sq. In.. Thus the force exerted by the cylinder at 500 PSI is 2454.5 Lbs. The force is applied at a pivot pin that is 19" from the center pin. The pin that the wiper die is pivoted on is 8-3/4" from the center pin. Thus there is a ratio of 2.171 to 1 to add into the calculation. That gives a force of 5325.72 lbs at the wiper die pin.

Converting this to torque is where I get lost on this. Maybe one of the engineers on here can check my math and take it from here.



Also, I measured the diameter (?) across the center of the bend in the plane of the bend and it was 1.858" and perpendicular to the plane it measured 2.001" I didn't cut it apart to check wall thickness, but I'm sure that it would be similar to other results already posted.

 

Very good information! Thanks for keeping this thread alive with great info like that!

Right on!

 

Looks like you are getting a pretty good bend off of that Hossfeld.

 

Anybody ever wonder how to figure out how much tube is consumed in a bend?

(CLR) Center Line Radius of die x Degree of bend x .0175

 

Ya know, i had to learn this formula when I was in college taking an engineering class. Almost wasteful knowledge, but usefull for just being something no other person would know.... campfire talk.

 

Actually, I have plenty of customers that have found it useful. It helps when you need to know how much tube to buy.

 

Let's keep the tube bending thread alive.

 

When are they going to give the price on the new bender coming out in June? I will be buying a bender and I like what I've seen so far.