At 10:06 PM 2/27/2004 -0500, David Scheidt wrote:
>On Feb 27, 2004, at 7:00 PM, Gerald Brazil wrote:
>
>>
>>Thanks to everybody who gave me a lot of good suggestions.
>>
>>I rejected the idea of wood because I wasn't confident that I would be
>>able to build it well enough. I then explored making one out of steel.
>>When I visited the place where I buy steel, I learned that you can't get
>>a nice slip fit in square tube because of the weld seam on the inside.
>>If you get an inner tube that will slide, it is a sloppy fit.
>
>Clearly, you need a better steel supplier. There are such things as DOM
>and HRS (hot rolled seamless) square tubes. Neither is allowed to have
>evidence of an inside seam. They cost more than stuff that might, or
>might not, have weld flash on the inside, but they exist.
>Incidentally, good quality square tube has the welded seam on the middle
>of a flat, not a corner. It's formed from round tube, using rollers on
>all four sides. Cheaper stuff (good enough for lots of structural stuff,
>though) is made by forming a flat into a square and welding the corner
>where the two edges meet.
My steel suppliers don't stock tubing that provide slip fits, either.
It's not the weld, it's the selection of ID/OD that's generally available.
It's the standard dimensions of seamed, seamless, DOM, and whatever
that keeps you from buying tubing that you can connect with slip fits.
There were several of us in a beginning welding class that thought that
slip fits would be a great feature in our projects, but standard tubing doesn't
work that way.
I'm not saying that you can't buy specialized tubing that will assemble
with a slip fit. I am saying that it is a product that is manufactured
specifically for that purpose.
Steve Shipley
Seattle, WA
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