NASCAR door bar design guidelines (Page 2 of 2)

On the bender, any of the JD Squared Model 3 or their copies work very well.  You have to be able to mount it and the best way is a pedestal that you can bolt down in the middle of a big open space (at least a 10' radius).  The real thing is about $325 shipped on ebay and plus around $250 for the die.

I have the Woodward Fab copy.  When I got it the combo was about $100 less for the combo (1 3/4" in my case) and it came with a degree wheel that was extra on the JD2.  We did have to bevel the edges of the follower die to keep it from creating chatter marks and even then, liberal use of grease was important.

I have never seen one of those capable of doing greater than 1".

With a regular bender you can do a continuous radius...sort of.  You calculate the total amount of bend, dived that buy the "shackle" width on the bender, bend that many degrees then move one shackle width, rinse repeat.  This will probably take a couple attempts but it should work.

I just went through this with my Supra and decided on an X-bar after much reading. The original was a straight X with one continuous tube and two shorter tubes to complete the "X". It was routed straight from the A-pillar to the main hoop.

The new version is 2 continuous tubes that are welded together and then tacoed. Stronger (all joints meet at nodes), meets all race series specs, much easier access, and more room for the driver when a window net is in place.

The angle to bend the tubing is something that can vary. It's depended on the width of the door opening and the desired mounting height you want the tubes to attach to the down tubes and where you want the bends in the two tubes to mate up.

I suggest you get some PVC pipe of the same general size and by heating it up with a "hot air" gun" or some other heat source you can then bend it to shape and determine the best angle. The bow outward is simply accomplisher by twisting the two tubes. You have to figure out the angle to notch the tube ends to get a good fit. Again use some scrap tube or PVC pipe to determine the angle of the notch.

FWIW, I got lambasted for suggesting to someone that they heat pvc pipe to make it bend for mockup. Something about dangerous fumes or whatev's.

(My experience is that it doesn't do what you want it to do and stinks like holy-hell).

Just take 2 straight pieces of whatever and make your angle. Measure that angle. Bend your tube a few degrees shy. You can stick pipe back in the bender and increase the angle but you can't straighten it (much) afterwards.

aside: I've got Bend Tech 3D EZ software that helps figure this maths stuff out. But I still do the method I describe above for many door bars.

I'll ask my cage guy, he may still have the paper it was written on. I was present during the work, but Dave uses computer software after taking basic measurements between mounting points.

No, you can't. Don't touch any bar that is to remain. A sawzall would probably be the better tool here.

I did not gusset bars together. The first pic is of the latest build with intended X-door bars. I wouldn't have welded them together, but one of my team mates got happy with the welder when my back was turned. I'd rather not heat the bars in the middle, so as not to lessen their strength. My fault for not making my vision clear.
This pic is of an add in bar from when the rules changed to require X- or NASCAR door bars on passenger side.

Yeah, but you must tie it to the main hoop.  That pig raced for many years in Lemons before being put out to pasture.  That pic is the birthing of Lipstick on a Pig.