On Fri, 15 Apr 2016 16:14:43 -0400, "Jim Wilkins"
wrote:

"Ed Huntress" wrote in message
.. .
On Fri, 15 Apr 2016 12:35:08 -0700, Larry Jaques
wrote:

On Fri, 15 Apr 2016 06:01:39 -0500, Karl Townsend
wrote:

I've got a project where i need over a hundred feet of 1.38 ID by
1.625 OD DOM tubing.

Turns out this is almost exactly the same size as 1 1/4 water pipe,
MUCH less expenisve.

Need to do a lot of machining and some bending of a small tab. Will
water pipe work as well?

I'd seen the term "DOM" mentioned a few times recently, and finally
decided to find out what it was. Here are some of the sites I
visited
in my research which might be of interest to you, Karl.

http://tubular.arcelormittal.com/ima...l_DOMSpecs.pdf

https://www.rme4x4.com/showthread.ph...s-D-O-M-tubing

http://metalsupermarkets.com/blog/di...seamless-tube/

https://www.youtube.com/watch?v=buu3Ytubp1s

http://www.jalopyjournal.com/forum/t...tubing.286487/

http://products.anssteel.com/item/st...un-1-1-4-2272?
http://products.anssteel.com/item/steel-pipes/galvanized-standard-steel-pipe/g-1-1-4-2272?&bc=100|1002|1016|1047|1049

http://www.industrialgroupco.com/ass...ifications.pdf


Pipe seems to be made from a mutt steel; whatever they find. If I
were making a simple bench or something for intermittent use or of a
light-duty nature, I'd use pipe, the cheapest.

If I wanted a chassis for a vehicle of some sort, I'd definitely
want
to go with DOM. It has a much higher safety factor. 1020 seems to
be
the standard the 4-wheelers use.

I'd also avoid 4130. Chromoly is nice, but is way too expensive and
too finicky for proper welds.

Not really. It's easy to weld with O/A or TIG. You just have to know
how it behaves, and if you won't learn that, I wouldn't want to ride
in anything you welded, anyway.

1020 is (or was) used on NASCAR racers, for two reasons: The weight
restrictions allow(ed) you to use tubing so heavy that you're at the
limit of practical strength anyway, even with 1020; and if (scratch
that -- "when") you crash it, you can cut out old tubes and replace
them without worrying about it.

--
Ed Huntress

I didn't have any trouble welding 4130 aircraft tubing tees for
practice.

Wasn't there a problem with chrome-moly frames so strong and stiff
they overstressed and killed the driver instead of progressively
absorbing energy?

--jsw

Old piper cubs were mild steel, so was the original Lotus 7.
Our Pegazair is 4130.