I'll most likely be building an interior cage in my fab class in a few months as long as i keep my job and get the dough for it.

my question is, i can get
1.625 x .134 HREW for $4.33/ft
1.75 x .250 DOM for $10.33/ft

what should i use and why?

the HREW should be plenty strong correct?


stay tuned for a rear flat stock bumper someone else will be making as well for his project to pass the class(think fab fours crossed with road armor and a persoal twist)

 

HREW sucks imo...

I would do most in CREW and some of the critical parts in DOM

1.75" x .120" Wall FTW

 

My opinion..

Do it right the first time:

1.75" x .120" DOM for any cage, whether, interior or exo.

Stay away from any HREW or CREW for tubing used for safety/proctection.

And .250 wall DOM is wAYY overkill for a cage (money better spent elsewhere)!

 

most home people cant bend .250 wall DOM

DOM isnt needed everywhere, circle dirt track guys do not use DOM on 90% of the cars, its not needed, they are manditory to use it around the drivers head. I think CREW if done correctly will be fine. But if I had the cash I would use the DOM 1.75" .120" wall

 

i think 1.75 x .120 is ~$8 a foot for me

 

Of course Chromoly but I think the cost is out of the question.

The second choice is accepted as a good choice by all the sanctioning bodies but usually overlooked because of the way the rules are written it looks like it is just part of the complete description of DOM tubing.

I am talking about CRS tubing, Cold Rolled Seamless, the only downfall is a 3-5% less elasticity VS DOM. It is not available everywhere but when you find it it is only slightly more expensive than HREW. In this part of California we can't get it but in the midwest annd east it is very common, I would have to buy a very large quantity to take advantage of the price difference but most of you can save a bundle.

 

chromoly requires stress releiving. I would put any but DOM for a cage. why spend all that time and effort for a decent outcome. go DOM on all of it...

 

CRS is an acceptable tube to use.......every bit as strong as DOM just not as well known. Check your NHRA, SCORE, & NASCAR rulebooks.......Very good tubing!

 

i dont need it up to NHRA Specs


my instructors who have been doing this all their life told me the 1.625 x .120 HREW would be fine

 

But who can tell you when that slow speed flop caves in a small lip on a large drop......

1 5/8" should be fine, IF properly triangulated and designed, a welding instructor is not a cage designer, not that they could not weld it up fine but if they don't have the proper design experience it may not be enough.

A perfectly designed cage could probably be made of conduit, if you don't have the design experience overbuild it and use gussetting correctly.

 

well one has a econo class dragster, 8.4 et at ~156mph?, 400hp, 1100lbs, 4 cylinder Natrually asperated, carburators and gas. with plenty of experience building tube chassis for drag cars, running chassis shops and working in chassis shops.


i was also planning on putting a lot more tubing into the design than i need

 

Just making sure......

 

yea, one of the other ones i wouldnt ask lol


and the 3rd one seems to know but he hasn't done much chassis fabrication. mostly engine building and machining


the class used to be chassis fab and high performance engines, but they took the engines part out.