Roll cage bar bending

[Rusty105]

I have a question about how the bars should be bent for a roll cage. NASA CCR 2005 States "15.6.5 Bends. None of the tubing may show any signs of crimping or wall failure. All bends must be mandrel type......" Does mandrel "type" mean done on a mandrel bender, or be smooth, kink free, crack free, etc. The question is can I bend the bars with a "JD2" type, or "Pro-tools #105" type bender. Other Sanctioning bodies specify bars that must be wrinkle free, and show no signs of wall failure. I just want to get a clear ruling on this before I start out on my project.

Thanks

Rusty

[Tims]

I am not familiar with the brands you mentioned, but if they are bent with a mandrel it will be fine. If it is bent with a muffler shop type bender it will not be okay. here is a link to a popular type of hand bender. http://www.tubing-benders.com/model3bender.html

[Rusty105]

And that type of bender would be acceptable??

 

Rusty

[Tims]

if used correctly it would indeed. The vast majority of cages racing in club racing are built with similair tools. care still needs to be taken to not crush or overbend the tubing.

[davidfarmer]

if you don't use a mandrel, the tube will likely be crimpled. I have a cheap hand-pump bender, and while it isn't fancy, it makes nice mandrel bends.

 

If you can visually see the pipe squashed/stretched, then you need another bender.

 

I tried one of these, but it didn't come with the correct size mandrel. Often, "pipe" is measured by inside diameter, but roll bar tubing is measured by exterior diameter, and you have to have the correct size mandrel or the tubing will "squash"

[davidfarmer]

http://www.lowbucktools.com/benders.html

 

here is the bender I have. Does nice bends, but you'll kill yourself if you do a lot of bending, but the price is pretty nice.

 

Dave

[Want2race]

I agree with David.. I have that pipe bender and its a complete piece! The low bucks model is the one to go with in my mind!

[vcavallaro]

I've been shopping for one myself and am leaning towards this one.

 

http://www.pro-tools.com/105.htm

 

The web site has a great pictures and video demos.

[turboice]

I am not familiar with the brands you mentioned, but if they are bent with a mandrel it will be fine. If it is bent with a muffler shop type bender it will not be okay. here is a link to a popular type of hand bender. http://www.tubing-benders.com/model3bender.html

 

That is the JD Squared bender. http://www.jd2.com/

[rppngears91]

if you don't use a mandrel, the tube will likely be crimpled. I have a cheap hand-pump bender, and while it isn't fancy, it makes nice mandrel bends.

 

If you can visually see the pipe squashed/stretched, then you need another bender.

 

I tried one of these, but it didn't come with the correct size mandrel. Often, "pipe" is measured by inside diameter, but roll bar tubing is measured by exterior diameter, and you have to have the correct size mandrel or the tubing will "squash"

 

did you say that orange bender, eventually worked out for you? or did you have to go with a different bender?

[dilbertgonebad]

Most shops do not use mandrel bends for cage work, most use what is called rotary draw bends. Rotary draw bends bending does not adversely deform tube wall. As do many forms of press bends (such as would be performed using the orange bender seen previous posts.

 

I do believe that the current rules are mistaken in their nomenclature but non in intent. In that it is important no to deform the pipe wall, as this would result in a weakness.

 

http://www.thefabricator.com/TubePipeFabrication/TubePipeFabrication_Article.cfm?ID=1444

 

Remember you want to make the cage using DOM (drawn over mandrel) (the material) tubing, and that you wish to use Rotary Draw Bends (the process) to bend your tubing.