As far as I know, there is no A36 spec for tubing. A36 just specifies a
low carbon mild steel composition. Any steel supplier that tries that
spec on you is saying "we have some square stuff with a hole in it that
a magnet sticks to" A513 has lots of subsections Type 1 is hot rolled
type 2 is cold rolled, type 5 is welded drawn (round only) A513 also has
lots of specs on squareness, wall thickness, corners, twist, etc etc. So
the real difference between A513 and A36 is that with A513 you have some
idea of what you are getting.

Will your 2" and 1-1/2" work together? Probably. Unless you get some
mill seconds, square tubing is usually some decent product. You are
looking at .060" clearance per side, more than enough to clear a weld
flash. You might have problems on the corners. Usually, the smaller the
tube the more square the corners are. Only way to tell is try it out.

The total of .120 is going to make a fairly sloppy telescoping joint.
You mentioned 24" sections, if the overlap is less than about 6" is will
flop a good bit.

DeepDiver wrote:

"RoyJ" wrote in message
nk.net...

Regular A500 square tubing is not uniform enough to get a good fit
plus there is usually a miserable weld seam. Also, A500 is likely
to be a much rougher surface finish, ask for A513 mechanical grade.


Actually, I was looking at A513. My mistake for writing A500-series.

Can you tell me the difference between A513 and A36 tubing?

Will 2" x 2" x 3/16" A36 (outer) work with 1.5" x 1.5" A36 (inner) tubing?



Choice one is to get the material that is made to telescope
toghether. Telespar is the usual brand name to specify.


That's what I've been searching for. Unfortunately, it seems that the
small-batch metal suppliers (like OnlineMetals.com and MetalsDepot.com)
don't seem to carry this stuff. I'm sure someone does, just haven't been
able to find a supplier yet.

If anyone knows of a local supplier in the San Francisco Bay Area, please
let me know.

Thanks,
Michael