DO I really need DOM tubing for front crossmember?

I called a couple of local steel suppliers and they say they don't carry it! I thought it was pretty standard stuff. I need a 28" length of 3". 3/16" thick would be good. Can I use something else? It's a T roadster so the car will be fairly light. What'dya guys think?

 

I guess it depends on a persons preferance, I think 3" is too big for the front cross member. I think 2" looks right, and strong enough for a banger or V8, especially at 28" width. DOM is good stuff but the seamed tubing would be fine also.

 

A good quality seamed tubing will be fine.

 

If your frame is 2x3 the 3" will look fine. 3" x 1/4 is probably easier than 3/16 to find.
Good luck with your car.

 

http://www.metalsdepot.com/products/hrsteel2.phtml?page=rndtube&LimAcc= &aident=

 

Or 2" sch. 80.

 

I don't know about pipe. I use 2 5/8 DOM because it tucks inside the top and bottom rail of a piece of 2 x 3 3/16 wall box tubing. IMO 3 inch comes out to the edges of the 3 inch tubing and looks a little large there. Just a personal thing.

Don

 

Taper the rails down to 2" for about 30" and us a 2" crossmember. Just looks better

 

D.O.M. is seamed tubing.

 

do not use black pipe for anything other than plumbing or bracing a body...

 

Like used for gas lines?

 

D.O.M stands for Drawn Over Mandrel. Just a post welding process to smooth and straighten the tubing. regular A500 MECHANICAL TUBING should be just fine. only Rat Rods use waterpipe for the front spring crossmember.

 

Black pipe will be fine and readily available almost anywhere. Back in the day, many figure-8 stock cars were built with black pipe, heavy but could take a beating all season.

Bob

 

Don't mean to piss on anybodys parade but black pipe is an absolute no no on any ch***is component. Schedule 40/80 is tested at the factory, ( only some is tested, not all), for leaks and relativly low pressure containment. It is not a structural component! A lot of black pipe is now Chinese and has questionable at best q.c.. It will not take torsional loads like seamed or D.O.M. will without failure. Like most things, and I'm guilty as anyone, things may have been used in the past and you may have gotten away with it, but...... Your taking the lives of not only you and your p***engers but all the soccer moms aroound you on some Chinese s**** iron?

Call Wintec and you'll have the piece that won't kill anyone in two days. Let the black pipe at Home Depot. I know we used it for roll cages back in the day and it failed regularly which is why no sanctioning body would even consider it's use today. If you think it worked back in the day you were probably one of the guys who wasn't going fast enough to break anything, (only kidding).

Leave that pipe to the rat rodders who are going to make it bad for all of us.

 

Koz,
You could build your roll cage out of PVC if you didn't crash.

Koz is correct here. Do not use plumbing pipe to build your hot rod, while on the subject don't use bed rails in place of angle iron either.

Finding DOM tubing in Santa Rosa should not be a real problem. There have been people racing out of Santa Rosa since before I was born and racers build race cars. Never the less if you cannot find DOM standard mechanical tubing will work as well.

 

Not that im plannin on using any for moving suspension parts, but can i ask why exactley we are not supposed to use galvanized pipe?
Just want to know so that next time this comes up in a conversation i can back up the statement with an explaination.

As for the black pipe. I hear the argument Koz is making, and its sorta new to me tbh.
I did a whole step notch out of various dimensions of square and rectangular "black pipe" backed by 4mm steel plate gussets and fish plates, and it seems to be holdin good for a car that can go up and down fairly quick and occasonally lay some sparks.
Sure, now that i know this i might think twice the next time i do something like this, but are we sure it is a "problem" for cars that dont really go faster that 80mph in the freeway and do an average of 30mph for 80% of their life?

 

LOL

 

I used 3" x 1/4" seamed tube for a rear crossmember with a perch before. Made sure the seam was facing down. Never had an issue.

 

I take it you posted this as a joke ?

Don

 

Technically speaking, the position of the seam in seamed tubing should not be an issue as the weld is supposed to be stronger than the parent metal itself. There is nothing wrong with seamed tubing used in the proper application. For suspension components such as ladder bars or four bars DOM is a must. This has to do more with tapping than structural strenght.

 

When galvanzing is applied, welding/heating it will produce toxic gases.
As will welding stainless steels. Chrome-6 or Chr-6 is cancer causing in minimal exposures. <less than 6 ppm.

 

I've had good luck with this place when I'm too lazy to make the trip into town.

http://www.onlinemetals.com/

 

Bonez,
The galvanizing process has a tendency to make the metal brittle. There are obvious reasons that people don't like to weld it, the obnoxious fumes being one of them, but the reason that the sanctioning bodies have decided against it is because it makes the metal brittle.

I think that we have a mild misunderstanding of what black pipe is. It had little to do with the color of the pipe and everything to do with its intended use. What is being called black pipe is made for use as a conduit for water or gas (as in natural or propane) I have not seen either in a square or rectangular tubing. This is not to say that it does not come that way just not that I have seen it that way.

 

In a word...Fatigue.
The roughest of estimates... maybe even mis-leading, so not really an estimate... is to say loading of 1/10th of ultimate strength, will likely cause to fail in fatigue.
after several number of cycles.
Brianangus? Squirrel? Semi-clued paging Squirrel...

 

Or a custom front or rear spreader bar.

 

Nah..... The parts falling off could hit you on the way!

 

hotroddon is correct, here's a good illustration of the process. When you work with dom tubing in quan***y you will notice the tubes in the bundles can vary several inches in length because they cut the pinched end off rather randomly.

 

Thanks guys! I picked up a length of 2-1/2" pipe, 3/16" thick in the s**** pile at work. We use it for the railing systems in our buildings. Should work well.