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roll cage materials sched 40 pipe vs. dom

k-bay xj

NAXJA Member #1356
Location
Va Beach, Va
I am currently planning a roll cage, and roof swap/convertible project for my xj, and I am still in the way early planning stages on this, so please don't kill me for the question I am about to ask, and yeah I have read every roll cage/convertible thread here and in other forums, and have only seen this once. While reading about cages on a CO K-5 blazer forum, they were discussing materials, and there was a picture of a guys very mod'd rig, chopped top, bumpers, rock guards, full cage, etc. Anyway, the guy who posted the pic said that every thing was made with schedule 40 pipe, not dom or hrew tube.
This sparked up a new round of questions to my welder/machinist buddies and they had no clue.
So here is the question: Is there a difference between 1.5" .120 wall dom tubing and sched 40 pipe that measures out to 1.66" OD and .140 wall?
I am guessing that there is, as pipe appears to be about 1/4 the price of tubing and a pipe bender (will bend 1/2" to 2") is $100 from harbor freight, versus $500 for a JD2 tubing bender and one die.
I don't know that much about metal, so that is why I am trying to find out here.
On the pipe strength side, I have seen lumber racks built from it that hold a buttload of material without even a budge, and also saw a bail rack on my buddies farm that had about 4000 lbs of hay sitting on 4 pipes that stuck out from the about 3-4 feet and it only bent about 2 inches.
Sorry for making this so long, but it has sparked my curiosity. Thanks
Matt
 
Rev - That is kinda what I am thinking, and unless I can get some solid proof that pipe would in theory hold, I will go with tubing. Just wanted to see if anyone knows the difference, if there is one between non threaded pipe stock and dom or hrew tube.
 
First thing. Tube sizes run O.D., pipe sizes run I.D.. Call your local pipe supply house and ask them for either sch. 40 seamless or sch. 80 seamless. All standard pipe is Hot Rolled Electrically Welded, thats why you want seamless. Its much cheaper than tube because it is more readily available. Oh yeah RevDan, cast iron pipe and pvc is for plumbers, any other pipe is for Pipe Fitters.
 
Without getting way too deep into it the simple answer is that pipe tends to be more brittle & less forgiving than tube. Now there are different grades of both pipe & tube & a good grade of pipe will out do a bad grade of tube any day. Apples to apples tube is a better choice to handle the loads in the use of a structural cage. Opinions vary, but that's my $.02.

Matt
 
As to the material sizes, 1.66" OD is not overly large slightly larger than 1.5" but the .140 wall size is about right. Lighter tubing in the 1.5 x .120 is the most common used for cages either chromo or mild steel.

You will be surprised how much weight the thicker wall size will add but it adds alot of strength too.

The Harbor Freight bender will not bend light-weight tubing and wont bend .140 either without kinking. You might getaway with bending .188 with a pipe bender but those jack-benders aren't real accurate.

You CAN bend .140 and up to .250 & larger pipe & tube with a GOOD quality tubing bender, it wont be easy but they'll do it.

I'd say get a good tubing bender & some .120 and have at it, dont cheap out on your cage. My last bender was about $900 including dies & the stand, Pro-Tools 109. Great tool though and it paid for itself many times.

Good luck!

-jb
 
I think the worst reason to use pipe is that most people do it with the crappy HF bender. If the bends suck it won't matter if you make it out of 4340. Now if you had a pipe bender that did good bends it starts to become more of a consideration. Pipe is absolutely not the best, but the fact is it has, does, and will work in many applications.

check out this thread: http://www.pirate4x4.com/forum/showthread.php?s=&threadid=216563 it's long, but near the end it gets good
 
do not use emt(electrical metallic tubing)for cages or exhaust systems..it is good for wiring,not strong enough for cages.emt puts out a harmful gas if exposed to high temp.you could use thick wall rigid conduit.....
 
tony597fitter said:
First thing. Tube sizes run O.D., pipe sizes run I.D.. Call your local pipe supply house and ask them for either sch. 40 seamless or sch. 80 seamless. All standard pipe is Hot Rolled Electrically Welded, thats why you want seamless. Its much cheaper than tube because it is more readily available. Oh yeah RevDan, cast iron pipe and pvc is for plumbers, any other pipe is for Pipe Fitters.

Amen Brother Tony! :worship:
Based on some of the steel tubing that I've bent-up, the metalurgy is different between drawn tube and blackpipe. The tubing is generally more ductile than sched 40 black steel pipe.

BLUTO (#636)
 
I forgot to add: I've bent some smallbore black pipe stuffed with fine sand (threaded and capped). This helped to eliminate kinks...BUT...it also depends on the degree and radius of the bend too ;) .....

BLUTO :)
 
This is the response I thought I would get, as I have never seen or heard of a cage being made out of pipe (except for that one I saw in a CO K5 site), and the fact that it is way cheaper than DOM probably says something about its strength. That sucks that the harbor freight bender is a POS, I was definitely liking the price over the JD2. Looks like I need to start searching for someone with a proper bender. Anyone know of one in Hawaii?
Thanks for all the info guys, I was already leaning towards DOM, just wanted to figure out the difference between the two. My machinist and welder buddies had no idea (arent they supposed to know a little bout metalurgy), and I am just a lowly knuckle draggin engine mech, so...
Matt
 
Has anyone ever done a write up on how to build an exo cage? Things like where to put the tubes for maximum strength without a bunch of excess that wasn't needed.
 
Here's my opinion for what it's worth. I'm not a metalurigist or anything like that but from what I've seen the design is the most important aspect of any cage. I've seen guys that I raced circle track with use such light weight crap as exhaust pipe and made it hold half-a**. Pipe is better than nothing, a pipe cage designed right is better than a dom cage designed poorly. Study the aspects of building a good cage and go with what you can afford, if you can afford dom then by all means go with it. Just my redneck thoughts.
 
Mirroring Cooter on this...Depends on what you want from the cage. Schedule 40 or 80 is plenty strong enough, but lacks the characteristics needed for proper deformation in an energy absorption design. It might work ok if all you need is protection in a turtle rollover...ultimately even if you use the best available DOM, Chromo, or other high quality tubing the geometry,fit-up, bracing and welding technique will determine if it will actually work. The best cage is only as good as it's tie-in points.
 
I have done more and more looking around this weekend and it seems like every 4x4 forum out there has had this debate about what kind of materials to use more than once, DOM vs HREW vs schd 40/80 pipe, so it looks like it wil never be a settled issue.
I am probably going to look into HREW because it seems to be a little less expensive than DOM. I am mainly looking for chassis stiffening, since the chances of me rolling while wheeling are slim, and if I do it will probably be a turlte roll, because I am being a jackass. Please don't flame me for doing a poser cage Beezil, its just that I'm in Hawaii and there isnt that many extreme wheeling or rock crawling options, just some minor trails and a lot of mud when it gets to raining. Unless of course I am missing out on some trails that anyone here knows about.
My heep was a govie mule for 12 years on Wake Island, so as you can imagine it is rusted to sh!t. The top is getting chopped as soon as I get new A pillars, probably a little like Rev's was done, but mine is a four door. I am thinking about welding the rear doors closed and if I have back seat passengers they can go Duke's of Hazard style.
Alright I am getting long winded on this again. Later
Matt
 
I'm also new and doing research about a roll cage for my XJ. One big concern for me, as this is my first roll cage, is to follow a proven design and material. I'm all for saving money but the roll cage may not perform properly if the design is significantly altered. Keep up the research and let me know if you find a roll cage builder that recommends schedule 40. Until then, hot rolled electric welded tubing may be the most economical choice.
 
bustedWagoneer said:
I'm also new and doing research about a roll cage for my XJ. One big concern for me, as this is my first roll cage, is to follow a proven design and material. I'm all for saving money but the roll cage may not perform properly if the design is significantly altered. Keep up the research and let me know if you find a roll cage builder that recommends schedule 40. Until then, hot rolled electric welded tubing may be the most economical choice.

You do know this thread has been dead for almost 3 years right?

:twak:
 
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