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View Full Version : Roll Cage DOM/HREW and Size



offroadzj
04-08-2007, 03:31 PM
What is the best material to use for a roll cage? I finally got ahold of a bender, and would like to start on my internal cage (decided against the external...f*** the body lol) I have done some searches, and saw there is some disagreement between HREW and DOM. Which is better, and what is the correct size to use?

offroadzj
04-08-2007, 04:50 PM
two more questions to add... (1)About how many feet of tubing is required to do a basic (but structural) interior cage in a ZJ? (2) Are there any decent free programs out there for designing a cage? MS Paint just doesnt do it... lol

zj95maxx
04-08-2007, 05:00 PM
Bend Tech is a program

Here is a buddies cage in the program
http://img.photobucket.com/albums/v314/rock_crawler/1%20Ton%20swap/My%20cage/Mycage1.jpg
http://img.photobucket.com/albums/v314/rock_crawler/1%20Ton%20swap/My%20cage/mycage2.jpg
http://img.photobucket.com/albums/v314/rock_crawler/1%20Ton%20swap/My%20cage/Top.jpg
http://img.photobucket.com/albums/v314/rock_crawler/1%20Ton%20swap/My%20cage/Passsideshot.jpg

offroadzj
04-08-2007, 05:21 PM
that is a nice program, but a little too expensive for me. Anyone know of a free one by chance??

zj95maxx
04-08-2007, 05:24 PM
there is this one..Google sketch up..again..pics from a friend
http://i16.photobucket.com/albums/b37/chewning37/Maxxsbumper.jpg

He hasn't fully figured the Tube part of the program, but its worth checking out cuz its free

offroadzj
04-08-2007, 05:33 PM
dogh... not supported w/ vista... argh

zj95maxx
04-08-2007, 05:35 PM
haha Sorry man

Kraqa
04-08-2007, 06:03 PM
1-3/4" .120" ERW

DOM is expensive and un nessisary. ERW will dent easier then DOM but if it an internal cage you wont' have to worry abotu that.

i woudl not go smaller then 1-3/4. 1-1/2 if you using DOM.

everyone around here makes there cage otu of erw or pipe. both hold up well. th epipe resists denting better then the ERW.

you build the strength into the cage. throwing material at it is the wrong way to build a cage.

and you shoudl buy around 180' of it. there will be crop left over.

Kraqa
04-08-2007, 06:04 PM
http://img.photobucket.com/albums/v280/Kraqa/New%20Buggy/Buggy4.jpg

http://img.photobucket.com/albums/v280/Kraqa/New%20Buggy/Buggy2.jpg



solid works rocks

offroadzj
04-08-2007, 06:14 PM
wow... are you serious about the 180'? That just seems like a lot to me.

Kraqa
04-08-2007, 06:39 PM
180 might be a bit high for a pure internal cage. doing anything in the front adds up. but you don't want to be short tube.

ELLLLLIOTTTTT
04-08-2007, 06:43 PM
Tube goes QUICK. You would be surprised. Of the 3 cages we've done, they were all HREW 1.75 x .120 wall. They are still holding up after a few light flops.

Kris hit the nail on the head. Structure > Material. Build it right with triangulation, bracing, and appropriate gusseting and HREW will protect you just fine.

ATL ZJ
04-08-2007, 08:27 PM
Four trips and two dents, one of them major, in my fresh 1 3/4" .120 wall DOM.. Only use ERW for sections where rock contact is impossible.

offroadzj
04-08-2007, 08:30 PM
now here is another question... lol. There is a guy on my local wheeling forum that owns a fencing business. He has all diameter sizes of 1/4" thick galvanized steel that he is willing to sell at wholesale if it will work... so my question is, will it work, or is galvanized too weak?

nate
04-08-2007, 08:41 PM
It would work, but that will be WAY WAY heavy!

offroadzj
04-08-2007, 09:01 PM
damn... that negates what I wanted to do. I want to chop the rear end to fab up a rear tire carrier and possibly shave some weight so its not as top heavy (maybe that wouldnt happen even w/ a regular cage, but i would think so...)

ELLLLLIOTTTTT
04-08-2007, 09:08 PM
Four trips and two dents, one of them major, in my fresh 1 3/4" .120 wall DOM.. Only use ERW for sections where rock contact is impossible.

If he's scraping rocks on his internal cage, I think he's got bigger problems. :D

mudforblood
04-08-2007, 09:33 PM
I dont think galvanized would be a good idea.Plus why does the dude have 1/4" wall fence posts? Usually fence posts are thinner wall. You can weld it but if you dont have a full face mask(over your eyes too) that is connected to an external pump or tank it will be very unhealthy. By the time you were done your eye balls would prolly just fall out.:eek::mrgreen:

As for the HREW and DOM debate I queitly lean towards the HREW aka pipe like Kraqa mentioned. I looked up and I had a post-it on my desk with some jibberish on it. I think I was comparing weight and price of DOM and sch. 40 A135(ERW also) pipe. translation and info: 1 1/4" sch. 40 = 1.662 OD with .140 wall is 2.718 pds/ft. and I pay $1.25 per ft., 1 3/4" DOMor HREW(I cant remember what I was doing)= 1.75"OD with .120 wall is 2.089 pds/ft. @ $2.90 per ft. I cant figure out what the other numbers.

180ft of toob
1 3/4" whatever DOM,HREW?? 376.02 lbs@$522
1 1/4" sk40 409.14 lbs@$225
1 1/2 sk40 489.24 lbs@$270
Also take into account waht bender you have pipe dies bend pipe, tube dies bend tube.
After typing all of this I think it might belong somewhere else.:D Sorry man. I would assume you have tube dies.

mudforblood
04-08-2007, 09:45 PM
I think my pipe OD numbers may be off, thats all from memory right now.:smt030 I can get better #'s tomorrow at work.

Here's a link to a big fence tube manuf. http://www.alliedtube.com/steel-tube-pipe/fence-framework/ Most of the wall thicknesses are on the small side. ie: 1 5/8" OD is .111 wall. on the heaviest. I'm not saying your wrong but it just seems uncommon to have 1/4" (.25) wall fencing or pipe in those sizes.

J B
04-09-2007, 12:26 AM
If it's PIPE, it's gonna suck for a cage. Pipe is not structural tubing. The material is cheap, and meant to hold some (relatively small) amount of pressure inside the pipe. Tubing is completely different, whether it has a welded seam or it's DOM. Obviously, DOM is better, because there's no seam, but even HREW is WAY above pipe on the strength scale.

Also, pipe has relatively thick wall thicknesses, so you're adding a ton of weight with not much strength.

Kraqa
04-09-2007, 12:43 AM
look lets not start the pipe vs tube debate.


ERW is not pipe. it is mechanical tubing that is welded. it is built very close to DOM tolerances but it has a seam.

Pipe is a difrent grade of steel, and yes it still has a seam.


I wheel with more then 15 people with pipe (SCH40 ) cages that hold up fine.

A number of peopel also have ERW. There is nothign wrong with ERW for a cage. it will dent easier then DOM, but thn again it takes ALOT.

Use ERW and fuck DOM. DOM is not required if your not competing. I've build a number of ERW cages. they work fine.

J B
04-09-2007, 11:49 AM
I wheel with more then 15 people with pipe (SCH40 ) cages that hold up fine.

Some people wheel with D35s and don't break them either. To make a cage out of schedule 40 pipe is just goofy. If you want to trust your life to a cage made out of schedule 40 pipe when you roll your rig ass over tea kettle, then go ahead. But to say that it "works fine" just means that it simply hasn't been put into a situation where it was really NEEDED.


A number of peopel also have ERW. There is nothign wrong with ERW for a cage. it will dent easier then DOM, but thn again it takes ALOT.



Now that I'll agree with. HREW is mechanical tubing, and would be adequate for a cage. Not ideal, but certainly adequate.

Kraqa
04-09-2007, 01:08 PM
Some people wheel with D35s and don't break them either. To make a cage out of schedule 40 pipe is just goofy. If you want to trust your life to a cage made out of schedule 40 pipe when you roll your rig ass over tea kettle, then go ahead. But to say that it "works fine" just means that it simply hasn't been put into a situation where it was really NEEDED.



Now that I'll agree with. HREW is mechanical tubing, and would be adequate for a cage. Not ideal, but certainly adequate.

i have no idea who you are. Or what your experience is but stay the fuck off pirate. You obviously have no experience with any of these materials first hend.

i KNOW what i'm talkign about and a SCH40 cage is FINE. i've personally seen a SCH40 cage do multiple rool overs with no distortion.

Pipe has gotten significantly better over the years. Here is a good example. GO use 1-1/2" SCH40 and make rock sliders. Then go make some sliders out or ERW or DOM 1 3/4 .120. the weight is abotu the same. Go wheel it and tell me what one dents first.

i'l bet you my life savings the ERW and DOM dents first.

J B
04-09-2007, 04:06 PM
You obviously have no experience with any of these materials first hend.

Uhh, I might have considerably more than you think.


i KNOW what i'm talkign about and a SCH40 cage is FINE. i've personally seen a SCH40 cage do multiple rool overs with no distortion.

I'm happy for you. So since you have seen ONE that did that, I'm sure it's perfectly ok. Based on your experience I think you need to petition all of the racing and rock crawling sanctioning bodies to let schedule 40 pipe be used for cages in competition vehicles.


Pipe has gotten significantly better over the years. Here is a good example. GO use 1-1/2" SCH40 and make rock sliders. Then go make some sliders out or ERW or DOM 1 3/4 .120. the weight is abotu the same. Go wheel it and tell me what one dents first.

i'l bet you my life savings the ERW and DOM dents first.

And I'll bet you YOUR life savings that a DOM cage of 1-3/4" x .120 wall tube is way stronger than one made of 1-1/2" schedule 40 pipe.

You seem to simply be talking about dent resistance. That's only one facet of the cage. The cage has to be structurally sound enough to hold up under the conditions of rollovers and such, and the material properties of pipe just aren't there. It's just not meant for that kind of purpose. The pipe won't hold up under bending or any sort of axial forces that tube will. There's a reason that pipe, using about as much material as an equivalent piece of tube, is a hell of a lot cheaper.

I'm not really meaning to argue with you, but I just hate for people to see a thread and think that building a cage with schedule 40 pipe they can pick up at Lowe's is just as good as building it with decent tubing. That's simply not the case.

Kraqa
04-09-2007, 04:53 PM
I'm not arguing with you. Your wrong.

this debate has been around for years, how many people do you knwo who have die or been ingured from a pipe cage? and if so was that material error, or cage design. If the cage is not designed right it doesn't matter what material was used.

go learn how to build a cage, you'll save alot of money in material.

Here i'l send you on a project. Go search the internet for up close pictures of pipe cage failures. If you do fine anything, its gonna be cracked weld's or unsupported nodes.

and FYI some racing regulations alow pipe cages. No i'm not going to show you links. Search it for yoru self on google. or POR for that matter. This has been covered millions of times. and if you read more then the first page of the threads you'll find out that other peopel have done the duedilagence and found the information.

J B
04-09-2007, 05:42 PM
I'm not arguing with you. Your wrong.

That's your opinion, and you're certainly entitled to it. I'll be having beers with some friends of mine after work tonight, and I'll run this by them. You might be able to hear the laughter from here, but I'm not for sure. These guys design and build off road vehicles for consumer and military use....from the ground up. Of course, they have to be financially liable for what they build, so that MIGHT be the difference. I mean, if YOU build a cage out of schedule 40 pipe, you're only putting your own well being at risk. These guys basically put millions of dollars at risk, so they have more incentive to make sure their asses are covered than you do.

I wish I could find the article of the all aluminum military vehicle they just built that goes into an Osprey...it's in SAE's Off Highway Engineering journal....but I can't seem to locate it right yet.


this debate has been around for years, how many people do you knwo who have die or been ingured from a pipe cage? and if so was that material error, or cage design.

I don't know anyone that has ever built a cage out of pipe, and I live in Arkansas, so that says something. Hell, bailing wire, duct tape, and booger welds are the rule of the day on some rigs around here, and I have still never seen a cage made of pipe.


If the cage is not designed right it doesn't matter what material was used.

That's an absolutely true statement. The problem with pipe is the standard to which it's manufactured...it's all over the map, simply because it can be. Its intended use doesn't actually require anything that's really that strong. So the alloy content of the steel is very loosely controlled, and so is the amount of impurities allowed in the material. So the issue is that you can't design around a material for which you can't get guaranteed, consistent properties. THAT'S THE ISSUE I'M TALKING ABOUT. I can get the exact alloy makeup for a piece of tube from the manufacturer...not what they shoot for, but EXACTLY the breakdown of the allow from the batch of tube that I have sitting in the shop. And if it fails, and someone gets killed, all of that comes under scrutiny. You can't get that for pipe. It's made to meet some minimalistic standard for holding internal pressure, and that's it.

But yeah, You could build a cage out of PVC if you wanted to, and get it to hold up....if you designed it properly.


go learn how to build a cage, you'll save alot of money in material.

Thanks, but I've been down that road.


Here i'l send you on a project. Go search the internet for up close pictures of pipe cage failures. If you do fine anything, its gonna be cracked weld's or unsupported nodes.

....and such is the failure mode of a cage made of almost anything from someone who doesn't know what they're doing.


and FYI some racing regulations alow pipe cages. No i'm not going to show you links. Search it for yoru self on google. or POR for that matter. This has been covered millions of times. and if you read more then the first page of the threads you'll find out that other peopel have done the duedilagence and found the information.

I'm not familiar with any sanctioning bodies that allow cages made of pipe....but if that's your claim, then you can link those if you wish. I know you said you wouldn't go to the trouble, but extraordinary claims require extraordinary evidence, so if you feel the need to prove your point, then go right ahead.

But don't let some of the less knowledgable wheelers on this forum get the idea the using pipe is just as good as using tube, it's just simply not the case. The whole idea of the cage is to save your ass. Why take chances by using pipe?

Tommy
04-09-2007, 06:24 PM
I am not arguing the strenght differnces or whatever. But how much do you actually save? I guess I could look the prices up, but I am lazy... I didn't price out anything other than DOM and my whole cage was only about $600 with two sticks extra.

zjguy721
04-09-2007, 07:02 PM
:popcorn:

I don't know the fucking difference between HREW and DOM, but I am learning something!

nate
04-09-2007, 08:02 PM
HREW is basically tube before it's run through the mandrels to make it DOM as far as I know.

mudforblood
04-09-2007, 08:53 PM
HREW is basically tube before it's run through the mandrels to make it DOM as far as I know.

Nope. Its a different process all together. HREW is technically speaking.. drawn thru a set of mandrels and heated and welded within close proxemity of each other. It starts as a flat plate then its formed into the tube shape and welded. DOM starts as solid bar then its heated and drawn thru mandrels to form one continuous tube(no seam)

nate
04-09-2007, 09:35 PM
Uh sorry but

DOM starts out as a sheet as well. It's rolled, welded and then drawn over mandels (D.O.M) to get rid of the inside seam and to make it more precise.

Pretty much an extra step over CREW or HREW.


I don't know why everyone has a hard on for DOM. I've seen lots of shit built with HREW or CREW... or even black pipe/poop pipe/sprinkler pipe and have yet to see a failure that was because of the type of tubing.

There's applications where you need DOM, but for a roll cage or something like that that isn't precise, I hardly see the need. If strength and weight is such a concern that HREW or CREW isn't strong enough, CroMoly should be considered.

mudforblood
04-09-2007, 09:40 PM
:punish: Now I'm fuckin pissed by the previous statements saying that DOM and HREW are the only thing for cages. Fuck that...get some info to back your "high end snobby ass my stuff is better because i run with the cool kids" mentality. Look at the facts before jumping to conclusions. Pipe is only called pipe because of the diameter sizes it is manuctured in. It is a nominal size to reference, not the actual dimensional size of tube. Also look at the carbon content and yield strenths in all tubing/pipe being used. Check out A135/A795 specs for "pipe", some of them are close if not better than the junk HREW being used on the fancy pants cages. A135 is ERW(electric resistance welded) minus the heat, which is not neccessary for strength at all times. As for DOM look into A106, its the same thing but stronger and its in pipe dimensions. Heavier yes, but still stronger.:flipoff2:

Here's another juicy tidbit to chew on. How about the posers that use their cage as an air tank.... that is made of inferior materials not "designed" for pressure. A135 has a pressure rating of 300 psi...I guess that is not very much pressure.:smt120 Pipe also has a CRR(corrosion resistant ratio) which "tube" does not, if you live in a certain area or dont treat the inside of the "tube" then your perfect cage will be infected by MIC(microbiologically influenced corrosion,yeah google that shit:flipoff2: ) and will be eaten away from the inside out. I'm not saying it will happen but at the very least the pipe industry has addressed the problem with special coatings, pass that onto.

I work in the fire sprinkler industry which is why I know those specs. If saving thousands of lives at one time isn't a "financial liability" then I dont know what is. More useless facts: fire sprinkler pipe has to withstand five times the weight of the pipe filled with water plus 250 pounds. It has and will be the only thing left in a building after a disaster, it's been proven and documented many times. Also alot of chain store buildings' roof structures are designed and reinforced to carry the load of the system and the rest of the structure is very light because of the fire rating provided(most of the steel roof will melt before the fire sprinkler pipe falls down)

I was only providing info on the price and weight differences earlier but now I am contesting the piss poor statements previously mentioned.:smt018 Dont run your mouth on shit you cant back up with pure facts. Stay tuned for more FACTS not opinions.

J B
04-09-2007, 10:40 PM
:punish: Now I'm fuckin pissed by the previous statements saying that DOM and HREW are the only thing for cages. Fuck that...get some info to back your "high end snobby ass my stuff is better because i run with the cool kids" mentality. Look at the facts before jumping to conclusions. Pipe is only called pipe because of the diameter sizes it is manuctured in. It is a nominal size to reference, not the actual dimensional size of tube. Also look at the carbon content and yield strenths in all tubing/pipe being used. Check out A135/A795 specs for "pipe", some of them are close if not better than the junk HREW being used on the fancy pants cages. A135 is ERW(electric resistance welded) minus the heat, which is not neccessary for strength at all times. As for DOM look into A106, its the same thing but stronger and its in pipe dimensions. Heavier yes, but still stronger.:flipoff2:

Here's another juicy tidbit to chew on. How about the posers that use their cage as an air tank.... that is made of inferior materials not "designed" for pressure. A135 has a pressure rating of 300 psi...I guess that is not very much pressure.:smt120 Pipe also has a CRR(corrosion resistant ratio) which "tube" does not, if you live in a certain area or dont treat the inside of the "tube" then your perfect cage will be infected by MIC(microbiologically influenced corrosion,yeah google that shit:flipoff2: ) and will be eaten away from the inside out. I'm not saying it will happen but at the very least the pipe industry has addressed the problem with special coatings, pass that onto.

I work in the fire sprinkler industry which is why I know those specs. If saving thousands of lives at one time isn't a "financial liability" then I dont know what is. More useless facts: fire sprinkler pipe has to withstand five times the weight of the pipe filled with water plus 250 pounds. It has and will be the only thing left in a building after a disaster, it's been proven and documented many times. Also alot of chain store buildings' roof structures are designed and reinforced to carry the load of the system and the rest of the structure is very light because of the fire rating provided(most of the steel roof will melt before the fire sprinkler pipe falls down)

I was only providing info on the price and weight differences earlier but now I am contesting the piss poor statements previously mentioned.:smt018 Dont run your mouth on shit you cant back up with pure facts. Stay tuned for more FACTS not opinions.

You're a little out of your element here. Pipe is meant for carrying fluids under pressure, and nothing more. That is actually pretty easy on the material, all things considered. Your 300 psi is nothing. That imparts VERY minimal stresses inside the pipe. Hell the power steering system in your jeep is running at 1000 psi, give or take. Modern common rail diesels? Fuel pressures WAY above that. 300 PSI is cake.

To compare fire sprinkler piping to mechanical tubing for use in a roll cage isn't even apples to oranges, it's like comparing apples to ball bearings, since both items are basically round in shape.

You're talking about steel used in two COMPLETELY different applications here. Note that the liability in the fire sprinkler piping isn't in making sure the building structure stays standing, it's just that the piping remains to perform its function (which, by the way, is more a function of the water running through it to keep it cool than it is of the material being so bulletproof that it is stronger than the structurals the building is made of). Fire protection is purely a life safety system: Can the occupants get out before the whole damn building burns down. NOTHING to do with anything else.

I've made my points, you guys can do whatever you want. When you're talking about the cost to build a cage, the cost of the materials isn't really that great...it's the labor involved. If you're taking your time to build the cage as being worth $0, then maybe you can justify using pipe. But a couple of my friends got injured tonight when they fell off their chairs from laughter at the fact that someone would use PIPE as a roll cage for safety. But what do these guys know...they're just engineers who build vehicles from scratch for a variety of purposes, one of which is for the Department of Defense.

Like I said, there's a REASON that DOM and HREW/CREW tubing costs significantly more than PIPE does. It's a material issue...nothing to do with your design or fabrication techniques.

There is no free lunch.

unforgiven
04-09-2007, 10:46 PM
well, one thing for sure you all certainly are an educational AND entertaining bunch. myself being essentially a newbie to modded jeeps, am learning quite a bit on this thread, while being entertained at the same time.
thanks guys.

J B
04-09-2007, 10:55 PM
Uh sorry but

DOM starts out as a sheet as well. It's rolled, welded and then drawn over mandels (D.O.M) to get rid of the inside seam and to make it more precise.

Pretty much an extra step over CREW or HREW.


I don't know why everyone has a hard on for DOM. I've seen lots of shit built with HREW or CREW... or even black pipe/poop pipe/sprinkler pipe and have yet to see a failure that was because of the type of tubing.

There's applications where you need DOM, but for a roll cage or something like that that isn't precise, I hardly see the need. If strength and weight is such a concern that HREW or CREW isn't strong enough, CroMoly should be considered.

Good call Nate, but some DOM is seamless, without the weld. It basically starts out as bar stock. It's usually named as such, so there shouldn't be any confusion.

Anyway, it's not really relevant to the argument at hand, but I'd thought I'd throw that out there.

Kraqa
04-09-2007, 11:27 PM
pipe is used in many structural instances.

I hope you do ask your military engineering buddy's. If they know anything they will laugh at you. Personally you can sit here and throw out refrences of yoru buddy's that dpo this and your buddies that do that. the main thing that is nissing fom this puzzle of what you've done, and the experience that you are applying here to back up your statments.

Pipe cages are so commonm it isn;t funny. and no one is dieing.

what exactly is the engineering standard you are workign towards for your cage? Did you knwo that competition cages move? Have you ever seen a competition buggy up close? all there cages are tweeked, bent and crushed.

Did you also knwo that U-Rck allows ERW cages? They only do this if it is built from a sanctioned builder. This is a quality control measure. And the shear fact that they are thinking abotu doing the same for SCH40 cages to shoudl make you cringe. Some stock car classes allow Pipe cages, why is that?

I think it is more relevent to govern the method of building a cage rather then the material. like a mandatory X behind the driver?

I've seen mill certs of pipe with 90,000 PSI Yeild stength. This is comparable to some DOM. And the statment of pipes quality is alover the map is pure BS squandered up in hopes that most newbies would take your advise and skip over it. All material that is massed produced and used in everyday engineering practices have a maximum and minimum quality standard. This is in regards for the Dimensions and the Material composition.

Do you honestly think in your mind that all companies are sellling material worldwide unsed in millions of engineered systems and structures with no set standard? Get off the crack pipe buddy.

Now you've got me irritated. i'l be getting mill certs from work tomorrow.

J B
04-10-2007, 12:06 AM
Kraqa, your grammar alone would make these guys laugh at you, much less your knowledge of the mechanical properties of "pipe" and "tubing".

I'm really not trying to bash you, given that you are an experienced fabricator and well respected member of this forum, but some of this is so outlandish from an engineering and safety standpoint that's it's absolutely unreal.

There might be a milspec for REALLY badass pipe, but my guess is that's not what you're using, because that shit would be 10x the cost of seamless DOM.

The ONLY reason to use pipe is because it's cheap.

Some of your statements are 100% erroneous....maybe not in the circle you are in, but in the big picture of things (to say that any structural material has a wide range of properties is at BEST misleading). But hey, if you have specific points to make...you know....because you're irritated, you post them, and I'll forward them on to my friends, and I'll post their replies.

mudforblood
04-10-2007, 12:06 AM
You're a little out of your element here. Pipe is meant for carrying fluids under pressure, and nothing more. That is actually pretty easy on the material, all things considered. Your 300 psi is nothing. That imparts VERY minimal stresses inside the pipe. Hell the power steering system in your jeep is running at 1000 psi, give or take. Modern common rail diesels? Fuel pressures WAY above that. 300 PSI is cake.

To compare fire sprinkler piping to mechanical tubing for use in a roll cage isn't even apples to oranges, it's like comparing apples to ball bearings, since both items are basically round in shape.

You're talking about steel used in two COMPLETELY different applications here. Note that the liability in the fire sprinkler piping isn't in making sure the building structure stays standing, it's just that the piping remains to perform its function (which, by the way, is more a function of the water running through it to keep it cool than it is of the material being so bulletproof that it is stronger than the structurals the building is made of). Fire protection is purely a life safety system: Can the occupants get out before the whole damn building burns down. NOTHING to do with anything else.

I've made my points, you guys can do whatever you want. When you're talking about the cost to build a cage, the cost of the materials isn't really that great...it's the labor involved. If you're taking your time to build the cage as being worth $0, then maybe you can justify using pipe. But a couple of my friends got injured tonight when they fell off their chairs from laughter at the fact that someone would use PIPE as a roll cage for safety. But what do these guys know...they're just engineers who build vehicles from scratch for a variety of purposes, one of which is for the Department of Defense.

Like I said, there's a REASON that DOM and HREW/CREW tubing costs significantly more than PIPE does. It's a material issue...nothing to do with your design or fabrication techniques.

There is no free lunch.

Bring some facts fuck head!!! Not just say that your engineer butt buddies think that its funny. That says that they have not done any reseach on alternate materials to be used in the same application. The cost has NOTHING to do with the quality or strength of materials, it only has to do with supply and demand. Look up how much "DOM and HREW/CREW" is used compared to how much [read closely] A135/A795(not A53) is used in a year. Think about it.... 5000 ft of A135 in one building compared to 200 feet on a half asssed cage...hmmmmmm.... I wonder which one willl be cheaper. Yeah you pissed me off and I will destroy your misguided ideals.

You have still not posted any hard facts defending your side of the debate, only misinformed half assed assumptions by some go with the flow designers, engineers, builders, welders or laborers(we have no clue). For all we know your douchebag friends are mechanics. Consider this: the gov't wastes so much money that it's not funny. If they have been informed of superior materials they have the wool pulled over their eyes. Please give me back my tax dollars because these dumbasses are wasting my money.:mad:

You have not addressed A106 which is DOM all the way. Look it up. If you are worried about strength then prove it. Give me yield strengths and carbon content and I'll consider it. Bring it on.:smt102 Prove me wrong.

Kraqa
04-10-2007, 12:15 AM
My grammar has nothing to do with my knowledge or ability.

plain and simple.

zj95
04-10-2007, 12:21 AM
My grammar has nothing to do with my knowledge or ability.

plain and simple.


Plain should be capitalized... it's at the begining of a sentance... :finga:

mudforblood
04-10-2007, 12:22 AM
Kraqa, your grammar alone would make these guys laugh at you, much less your knowledge of the mechanical properties of "pipe" and "tubing".

I'm really not trying to bash you, given that you are an experienced fabricator and well respected member of this forum, but some of this is so outlandish from an engineering and safety standpoint that's it's absolutely unreal.

There might be a milspec for REALLY badass pipe, but my guess is that's not what you're using, because that shit would be 10x the cost of seamless DOM.

The ONLY reason to use pipe is because it's cheap.

Some of your statements are 100% erroneous....maybe not in the circle you are in, but in the big picture of things (to say that any structural material has a wide range of properties is at BEST misleading). But hey, if you have specific points to make...you know....because you're irritated, you post them, and I'll forward them on to my friends, and I'll post their replies.

STFU!!!!!! You have yet posted any info backing your or your faggot buddies accusations. All you bring is BS. PROVE ME WRONG!!!!!! Until you can bring facts to this thread go home and hump your sister!

J B
04-10-2007, 12:29 AM
Bring some facts fuck head!!!

I have brought plenty, without resorting to any name calling. You do the same, and then we can actually have some sort of discussion. You seem to be bashing the indivduals that have the techincal skill to design a lot of this mess, while professing that the laborers that build it really know all the answers.

The truth is that some guys design it, and other guys build it, and every now and then, you find some guys that do a bit of both.

Both skills are necessary.

You're obviously one of the the guys that builds this shit, based on your responses. The engineers would eat you for lunch. But......most of those guys have never struck a weld. They can learn from you, and you can learn from them.

Every now and then, you run into people with BOTH sets of skills. These are the people I'm talking about.

J B
04-10-2007, 12:33 AM
STFU!!!!!! You have yet posted any info backing your or your faggot buddies accusations. All you bring is BS. PROVE ME WRONG!!!!!! Until you can bring facts to this thread go home and hump your sister!

Wow, with a response like that, you're OBVIOUSLY the expert in this field. I'll shut up now, and let YOU take over.

:shake:

Kraqa
04-10-2007, 12:50 AM
I have to step in at this point. This is a technical argument, as frustrating as it is. Please don't resort in name calling....well not behind someones back. you dont' knwo this guys buddies.

mudforblood
04-10-2007, 07:33 AM
Sorry for my poor responses. It really bothers me so I got out of hand, sorry again.:(

I got upset because I didnt see any specs to back the other side of the discussion.. only statements that its better because they said so. I will provide useful information instead of running my mouth from now on. Sorrry once again, my bad.

The grammar comment is what put me over the top. I am calmed down now. Proceed with the discussion and delete my ignorant posts as necessary.

J B
04-10-2007, 09:11 AM
I can't post any specs because pipe doesn't really have a mechanical specification, since it isn't meant as a structural member. You know as well as me that there are plenty of specifications as far as working pressure, burst strength, etc., but that's apples to oranges.

Like I said, it's the inconsistency with the material that makes pipe a poor choice for anything structural. You just don't know what you're getting (in relative terms here).

On the opposite end of the spectrum is material meant for aircraft use. Even simple things like bolts meant for aircraft are damn expensive, simply due to the quality control on the materials and manufacturing. When a designer uses that fastener in an aircraft, the factor of safety is pretty damn thin, in order to keep the weight down. So, if there's a defect in a single bolt, that could be disasterous for the aircraft.

Kraqa
04-10-2007, 07:36 PM
I have the Specifications and mill certs from sch40 pipe and i'm waiting on the info for the DOM and ERW. I will post up once i have the complete comparison.

Kraqa
04-10-2007, 07:54 PM
Just Somehting to keep you busy for now.

All pipe is manifactured to the ASTM A53 Standard.

The two most common grades used are A and B

I will post up the Mechanical Properties once i get my hands on them. (yeild, tensile and elongation)

If this thread gets lost in the archives i'l be choked i have two engineers and three steel suppliers working on getting me this info.

mudforblood
04-10-2007, 08:13 PM
I have the Specifications and mill certs from sch40 pipe and i'm waiting on the info for the DOM and ERW. I will post up once i have the complete comparison.
I'm still looking for the detailed specs I found. We discussed it a little on a local board, I'll post some of the info we found.

It started as a square vs. tube question

This is the better part of an equation to determine deflection of a piece of structural tube, round or square made of steel
D=(w)(L^3)/48/(E)(I)

D= deflection, it will be used for our measure of strength.
W= weight or stress on the tube
L= length of the tube stressed (additional calcs used to place the weight in the middle)
E= modules of elasticity, for all steels it is considered to be 30,000,000psi.
I= Moment of inertia.

We'll use 1" tube, round and square. It will be 24 inches long and weighted with 1000lbs at its center. The (I) for 1" round tube with a 0.042" wall is 0.01453. For 1" square tube with same wall is 0.02467. So we already know its stronger but lets keep going. I used an online calculator for the equations and calculated with the load 12 inches from each side on a 24 inch piece.

(1000)(24^3)/48(30000000)(.01453)=.330 inches of deflection for the round.
(1000)(24^3)/48(30000000)(.02467)=.194 inches of deflection for the square.

Its like a 70% difference. Thats why the roll over protection on huge crawlers tends to be made of square tubing.



This was the pipe I covered when i did the research. I didnt even scratch the surface, didnt even mention the 135. There are different grades of 53 as you can see, 53a 53b 53f and probably more. The 106 comes in 106a, 106b, 106c, there is way more to pipe and tube than one would ever imagine.

ASTM A53F Continous Weld 25,000 45,000
ASTM A53A ERW or Seamless 30,000 48,000
ASTM A53B ERW or Seamless 35,000 60,000
ASTM A106B Seamless 35,000 60,000
ASTM A252-2 ERW, Smls or DSAW 35,000 60,000
API 5LA CW, ERW, Smls or DSAW 30,000 48,000
API 5LB CW, ERW, Smls or DSAW 35,000 60,000
API 5LX-42 ERW, Smls or DSAW 42,000 60,000
API 5LX-52 ERW, Smls or DSAW 52,000 66,000
API 5LX-60 ERW, Smls or DSAW 60,000 75,000

I went back and searched my sources for the 135. Here are the specs on it, it is some pretty good pipe.
Its ERW pipe, ava in 135a and 135b. Carbon content in 135a is .25%, 135b is .30% Minimal tensile strengths for the 135a is 48,000 for the 135b is 60,000. Compare it to DOM tubing; the last 2 numbers in SAE tubing are the carbon content so 1020 DOM would have .20% carbon. Carbon is strength to an extent. The pipe does not hold DOM tubing dimensions, its not even close. It holds withing 12% on the wall thickness, DOM will hold within 1% so the min tensile and yield is less on the pipe. Still good pipe, I cant believe all the crap that guy took for using it.




Where did you get the I (moment of inertia) from?

Also sprinkler pipe is listed as "A135 grade A/ A795" right on the pipe. Under A795 it can only have a plus or minus of 5% on the variation of weight per foot. Under A135 its plus 10% and minus 3 1/2%. So that would make it plus 5% and minus 3 1/2% for sch 40 sprinkler pipe. With less variation it is stronger than A53, I think.http://www.pgh-offroad.com/forum/images/smilies/017.gif At least more consistent at a minimum.




I= 0.049(D^4 -E^4)

I = Moment of Inertia
D = outside diameter of tube
E = inside diameter of the tube


There are a few threads on Pirate discussing pipe vs tube but I'll spare the original poster the drama and not link them. Buy a red star and search for it.:D Yes I'm not so cranky today....Mondays suck.

mudforblood
04-10-2007, 08:39 PM
Important: Do not use A53 grade F pipe. The seam is fusion welded and is very weak. It is the type of pipe that can be bought at Home Depot or similar store. Most of it is made in another country and is very low quality steel. Just threading or welding it you can tell the difference between that and A135 of any grade. A135 is mainly the minimum specs that sprinkler pipe follows. A795 is usually just a secondary standard that is followed. Most of them use both which makes the quality even better. Of course those are only minimum satndards to follow and not an exact representation of every piece. Every manufacturer has numerous types sizes and qualities of pipe designed for specific benefits ie:flow, corrosion, weight, price, and strength. Here's a few trade names off the top of my head: dynathread, dynaflow, superflow, megathread, ezthread and the list goes on. Each one is trying to "one up" the other, its kinda like tires, they all have their place.

A106 is used in the oil field industry. It is DOM in all respects and is made per nominal pipe dimensions instead of OD or ID dimensions.

As I was typing this I found my link to the specs: http://www.indpipe.com/product_f.asp good stuff

mudforblood
04-10-2007, 08:46 PM
How do I copy pdf. to post on here?

In the meantime here's some strengths of A106 pipe just for a thought.
yield strength and tensile strength respectively
gradeA = 30,000 and 48,000
gradeB = 35,000 and 60,000
gradeC = 40,000 and 70,000

offroadzj
04-10-2007, 09:10 PM
ok ok ok, now im starting to get confused? Who is on who's team... lol. Sorry, but I have to say, I am learning quite a bit in this whole mess.

mudforblood
04-10-2007, 09:20 PM
ok ok ok, now im starting to get confused? Who is on who's team... lol. Sorry, but I have to say, I am learning quite a bit in this whole mess.

I'm on neither side I'm only posting info from now on. Opinions are like assholes... everyone has one and everyone thinks everybody elses stinks.:D

I edited my last post in case it confused some one. A106 is also pipe. I'm still looking for tube specs.......

J B
04-10-2007, 10:50 PM
Most of it is made in another country and is very low quality steel. Just threading or welding it you can tell the difference between that and A135 of any grade.

Mud, this is EXACTLY the kind of thing I'm talking about. The mechanical properties tolerance of this stuff is VERY loose compared to tube, because it's not meant to be structure.

Any steel is going to have certain properties, but what that doesn't factor in is impurities in the steel that weaken the final product. That's tightly controlled with any steel structurals, because our legal system will ensure that you get your ass sued into oblivion if it's not.

Ever seen pipe failures vs. tube failures? The tube fractures and tears cleanly, whereas the pipe is more rough and jagged. That's the looseness in QC of the material being used for pipe.

Like I said, there's a REASON that tube costs more than pipe. That's probably the biggest part of this debate that you just can't argue against.

mudforblood
04-11-2007, 12:51 AM
Mud, this is EXACTLY the kind of thing I'm talking about. The mechanical properties tolerance of this stuff is VERY loose compared to tube, because it's not meant to be structure.

Any steel is going to have certain properties, but what that doesn't factor in is impurities in the steel that weaken the final product. That's tightly controlled with any steel structurals, because our legal system will ensure that you get your ass sued into oblivion if it's not.

Ever seen pipe failures vs. tube failures? The tube fractures and tears cleanly, whereas the pipe is more rough and jagged. That's the looseness in QC of the material being used for pipe.

Like I said, there's a REASON that tube costs more than pipe. That's probably the biggest part of this debate that you just can't argue against.

You have to look at all of the info I provided. A53 type F is common in chain stores but it is by far the only type of pipe made. The fire sprinkler industry is a close knit underground group of people. It is one of the few components of a building that are hopefully never used which in turn puts us on the blacklist when it comes to paying for intial construction costs. They are a necessary evil that nobody likes, especially engineers, architects and property owners. The cost of pipe is on the bottom of the list when it comes to a quality system. The biggest costs are the controlling fixtures of a system.

The reason that "tube" costs more than "pipe" only has to do with supply and demand, it has very little to do with the end product. Once again, please look at the specs I have provided. A53 type F is the worse case scenario, the rest of them can be closely compared to the "tube" being used in high dollar cages. I have personally researched the pros and cons of using one over the other and came to the conclusion that it doesnt matter which one you use. The biggest factor is what type of material used and how its built.

Run some calcs on comparable materials then decide which one is better. Most people are turned away only because its called pipe, meanwhile all pipe is technically tube. Most "pipe" is made by a "tube" manufacturer which dont even make the "tube " that most people use.

Please post up specs backing up tube before it gets shot down the drain. What is the most commonly used tube? A513 1008, 1010, 1026 or what??????? Tube and pipe are only general statements not hard facts, only dimensions.

OverkillZJ
04-11-2007, 10:55 AM
Holy crap... how did I miss this thread...

You're all nucking futs....


I used DOM considering I felt $.40 a foot was enough peace of mind over all the debates. I felt safer that way, but frankly, it's largely a matter of opinion.

You're all arguing yourself in circles.

violatedppl
04-12-2007, 01:59 AM
like stated before I believe the big difference between pipe and tube is the size. sorta like sheet and plate steel. 3/16 under= sheet anything over 3/16 is plate. same idea. now the throw a screw in the mix what about chromoly. would be a bitch to tig a whole cage, always another option.

J B
04-12-2007, 08:50 AM
Ok, the more I think about this, the more I think I realize what's going on here.

Some PIPE is going to be made to a decent quality standard (and that's obvious by the specs posted)....I guess basically like tube, except in pipe sizes. But I would think this would only commonly be used for sizes that are much larger than you'd build a cage out of......3" or 4" or larger. Honestly, that never even corssed my mind. So, I'll concede that point. I mean, there's a 20" high pressure interstate gas pipeline that runs through my area......I'm pretty sure they didn't source that pipe from Lowe's.

BUT, I think what MOST people are going to use if they're going to use pipe is the shit that you can get at your local hardware store or Home Depot or something. That stuff is NOWHERE close to having the strength that HREW tube would. Honestly, when "pipe" was mentioned, that basically all I was thinking about.

The pricing to me still shows it all though. Yes, there are market forces of supply and demand, but if the products were more or less interchangeable, people would be using them as such, and I think the price differences would go away.

Kraqa
04-13-2007, 12:12 AM
pipe spec's are for all sizes of pipe.

and most hardware stores don't carry 20' peices.

when you order pipe around here type F is a special request.