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Is schedule 40 pipe strong enough?

TruckNutzDude

TruckNutzDude

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I'm diving into the roll cage part of my project this spring and I need to know if this pipe will be strong enough. It's avalable in 1-3/4" diameter with a .185" wall thickness (I think) and it's about half the price of DOM and slightly less than HREW tubing. I have done some research on cage design and I plan on a lot of triangulation along with tying it into the body mount bushings. I believe I have heard of some people using schedule 40 pipe but I'm not sure about it. I doubt I'll ever roll my rig, but if I do I know the stock half cab will not be enough. I'm open to any kind of suggestions on how I can make this pipe work for a safe roll cage. Thanks guys! /forums/images/graemlins/bow.gif

BTW If the post doesn't catch anyones attention I won't cry myself to sleep if it gets moved to another forum. /forums/images/graemlins/waytogo.gif
 
I think most people are going to say no. I guess it all depends on your piece of mind. I have people tell me that my HREW tubing was not a good choice and I've seen Schedule 80 pipe hold up fine to multiple rollovers. I would at least go with Schedule 80. That is what my side armor is made out of and it has held up pretty well.
 
What is the difference between schedule 40 and schedule 80 pipe? I'm pretty sure the 40 pipe has .185 wall thickness, so does that mean the 80 pipe has a thicker wall? /forums/images/graemlins/thinking.gif
 
First off, pipe is generally frowned upon for cage structure. The problem is that "pipe" is wide range of products. Could be anything from seamless steel pipe to cast iron pipe. My grandad builds a lot of stuff from he calls "Double Walled (Sched 80) Black Iron Pipe". Which isn't iron at all, it's steel. Wall thickness per Schedule changes with size. 12" Sched 40 pipe has a lot thicker wall than 2" Sched 40 pipe.

Generally only tubing is rated to carry structural loads. Pipe is rated for max operating pressure as some sort of conduit of water, steam, compressed air, oil, etc. While possible to extract an approximate structural strength from a pressure rating, it's not commonly done.

As a guideline the SCORE rule book calls for at least 1-3/4" x .120 wall steel tube in a cage structure for a vehicle the size of a K5. At some point in vehicle weight (8k lbs I think) they start requiring 2.0" x .120 wall.

If it is steel pipe and you can bend it wrinkle-free then it MAY be OK. Why not just get the stuff (tube) intended for the job?
 
As usual, ntsqd's post has it pretty much all summed up.

I'll only add 2 points.

To clarify on the "anything from seamless steel pipe to cast iron pipe" point. Even if it is "steel", there are SO many grades and it's not really clear on most. Much of what you buy as "pipe" also lacks real specs on metal content. In particular, rumor has it that much of the "common" pipe you find is built in Russia from random scrap and is never consistent, often brittle and with inconsistent wall thickness (off-center ID).

And you said yourself that pipe is only "slightly less than HREW tubing", so why is there even a question? There is a reason that HREW is considered the "entry point" or "lowest acceptable" material for cages by most people "in the know". The only time you see people pushing "pipe" for cages, it's generally because it's "cheaper". And they maintain that it's good enough not on engineering principles, but based on anecdotal evidence or "opinion". They also generally wind up with heavier cages by going thicker/larger to recoup the loss of material strength.

I'm not saying in any way that you can't build a pipe cage to hold up. I'm not saying that those who use pipe are "idiots" or anything of the sort. But when HREW is close in price, I would not even consider pipe as an alternative…
 
You guys have good points. In reality I was only looking at this as an option because of cost and avalability. The only close steel shop doesn't carry or can't get DOM or HREW tubing, just schedule 40 pipe /forums/images/graemlins/doah.gif I believe the pipe was somewhere around $8 for 10 feet. Way cheaper than tubing IIRC. /forums/images/graemlins/dunno.gif I haven't priced out tubing from any local places yet, just going by word of mouth. /forums/images/graemlins/whistling.gif
 
I think the biggest issue for me is this:

Have you ever picked up a 20' long piece of sched 40 pipe? Its freakin heavy. I cant imagine building a cage out of 100+' of it. Thats a pile of weight.
I dont know how the weight compares to HREW, I dunno what HREW even stands for, but I do know the piece of sched 40 pipe I have here is very heavy.

Mike
 
The way I have been taught is that pipe is for "POOP" pipe is ment to carry fluids,gases, it is not a structural metal.

HREW....hot rold electric welded you will notice that this tubing has a welded seam down the middle of it. Can be use as structural metal..ie roll cages

DOM....drawn over mandrel...no welded seam so its going to be stronger than HREW. does not have a place to split when you are bending a roll cage.

you can bend both pipe and tubing but they require different types of benders
tubing...JD2 type benders
pipe.... the orange pipe benders from harbor frieght

/forums/images/graemlins/grin.gif /forums/images/graemlins/thumb.gif
 
DOM is just HREW with more work done. It still has a welded seam, you just can't see it very well.

And the JD2 style benders also have pipe dies available.
 
I have used, and will continue to use 1.5" (thats 1.9" OD)sch 40, A53E pipe for roll cages on my own personal rigs, and rigs for anyone who requests it.

I have had good luck with this schedule and grade of pipe for offroad use.

One note that anyone bending seemed tubing should pay attention to... When possible, put the seem to the inside of the bend.
 
I think I read somewhere that you were using it which is why I asked this question. I think I may be able to get some 1-3/4" roll cage tubing from a friend who owns a fab. shop. I will most likely use 1-1/2" or 1-3/4" pipe for the rest. The pipe will be used mostly for bracing and mounting. The cab part of the cage will be made in something stronger/lighter. /forums/images/graemlins/waytogo.gif
 
HREW, (hot rolled electric welded) is your best bet if you want to do it right structually and on a budget. I buy a 20 foot stick of 1.75 X .095 for 37$, it's cheaper tham 4130 DOM a little easer to bend, but structually safer than pipe. Keep in mind pipe is very soft.
Either way you go if you use something that has a seam in it make sure the seam is on the inside of the bend, this is very important. A nasty role over could split the seam if it's to the outside and become shrapnel :blush:
 
Dumb question: is "schedule 40 pipe" the standard black pipe you find in the hardware store for plumbing? Or, does it look just like tubing but is measured differently?
 
heavy4x4 said:
Dumb question: is "schedule 40 pipe" the standard black pipe you find in the <a href="http://www.srch-results.com/lm/rtl.asp?k=hardware%20store" onmouseover="window.status='hardware store'; return true;" onmouseout="window.status=''; return true;">hardware store</a> for plumbing? Or, does it look just like tubing but is measured differently?
Click to expand...

schedual 40 pipe is what you would find in the hardware store but most of the time the ends are already threaded. Because it's primary use is for plumbing or gas lines.
Pipe is measured by the inside diameter, the hole in the inside of the tubing and is either schedual 40 or 80. 80 being the heaver or thicker walled of the two.
Tubing is measured by the very outside diameter if the tubing and comes in various wall thicknesses. Example 1.75 X .125 wall, 1.75 is the out side diameter while .125 is how thick the wall is. therfore inside diameters of tubing, depending on wall size will vary.
Something to keep in mind when purchasing a bender, the dies for the bender will be drasticaly diffrent.
 
smash metal said:
Keep in mind pipe is very soft.
Click to expand...

Some pipe is soft and some is hard...it all depends on what type of material is used in it. A53 and A106 are good for what we do... A53-A being probubly the best because the A106 is harder to find and there is no material streingth gain. These types of pipe have very similer material properties and seam type as the HREW that most people refer to...the material is just sized differnetly.

schedual 40 pipe is what you would find in the hardware store
Click to expand...

Sch 40 is just the way that "Pipe" is measured. It has nothing to do with the material or tolerances.

Pipe is measured by the inside diameter
Click to expand...

Nope its measured by the "Nominal Dia". The outside diameter actualy stays the same from the different thicknesses of pipe. Forinstance 1-1/2 has an OD of 1.900" and that stays the same for all the different Sch's. Then the ID changes: Sch40=1.610" Sch80=1.500" Sch160=1.338" and XX-Hvy=1.100"

black pipe
Click to expand...

This is a common term used for "junk" pipe...but in reality is just refers to the coating put on alot of pipe. You can even get DOM and Square Tube with the Black coating on it.


There are alot of misconseptions and bad info running around about pipe.
 
a welders 2 bits

I'm a pipe welder by trade and can say all the responses are totaly acurate. I use alot of "pipe" sch 40 and 80 in structural work too, the big problem being of course wieght. The general rule of thumb we use at work is simply all seams on the inside of whatever we are building, gussets help alot too. Seams on the inside looks better but more importantly protects the welded joint from direct damage. Wall thickness of pipe changes depending on schedual and pipe diameter. One thing to consider is unless you are racing, a cage built out-of sch-40 1.5" (2" OD) will hold your truck together, most rollovers are relativly slow and DOM tubing is engineering overkill if your not crashing at 85 mph. Your truck frame will come apart before your "pipe" cage will. The biggest problem I've seen with cages, both DOM and pipe is the fabrication is poor and the welding totaly crap. Don't use flux-core wire or 6010-13 rod they both lack ductility, use either dual-shield wire or preferably a 7018 series rod. Be careful about the "heat affected zone" not so critical on pipe but critical on tubing, too much heat and you can embritle the weld and the area around it.
 
I am using 1 1/2 sch40 hrew pipe. for my cage which is also the same thing as hrew 1.90x .145 tubing and cost 1.50 per foot. I wouldn't use anything less than .135 wall. thats what nhra and nmro require. I know alot use thinner and even someone post up a few about using 1.75x .095 not that is scary less waith but it isn't gonna hold up to 6000 lb blazer. just .02
 
How about using the stronger 1.75" DOM .120 for the main structure of the cage (hoops) and then using the HREW for the triangulation pieces that don't get bent? This would yield a safe strong cage a little cheaper than an all DOM cage wouldn't it? I need to build a cage for my rig soon, thinking this is how I might go. Hoops and halo DOM, the rest HREW...

??? Good idea ???

I did use some pipe for some armor, only 10 feet total, and man that stuff IS heavy. I would definitely not use pipe for my cage. My buddy used pipe from OSH on his scout for a roll bar, I DEFINITELY would not trust that with my life in that rig, it already weighs a ton. The pipe bends are wrinkled too, so basically IMO there is no strength there.
 
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