On Wed, 06 Feb 2013 14:39:37 -0800, "Bruce L. Bergman (munged human
readable)" wrote:

On Sun, 03 Feb 2013 10:19:47 -0600, Ignoramus19840
wrote:

As part of that lot of steel stock that I bought recently, there was a
big bundle of "structural tube", which is steel tubing 2-6 inches
diameter, with walls 1/2 to 1 inch thick.

I hae to admit that I have neer seen them used anywhere, other than in
airports. What are their uses, exactly?

Lots of places - For starters, any "Lally Columns" in the middle of
your basement to hold up the house above you are going to be in the
mid-range 1/2" wall range or thicker, with some matching serious beam
saddles.

I could use a few chunks of it for replacement fence posts holding up
the gate hinges - Make the car bounce off rather than bend the post.

In Chicago, the same thing for building a Snow Plow Proof mailbox post
and arm assembly. Especially useful if you've got a renegade plow
driver trying to snick the wood ones off on purpose as a sport...

Paint it wood brown so they can't tell, and you can hear the
"CRUNCH-PTANG!" and "SCREECH!" of the plow spinning the truck around
before snapping off instead...

They cheat and use Sched-40 Pipe and fill Crash Posts with concrete -
but if you're dead serious about stopping a car before it hits
something - like in front of a 2500 Gallon Propane Tank - that
structural tube will do it if you plant it in enough footing concrete.

My second question is, if I want to weld a tube to a plate, do I need
to bevel the tube for a proper joint?

Depends on how the forces load it - but for ultimate strength yes.

-- Bruce --

Call Steve, he's trying to build a cannon and 6" pipe with 1" walls
might be just what he wants :-)

--
Cheers,

John B.