[Antennas] Texas Towers Aluminum Tubing, A Warning.

2002年8月26日 14:25:38 -0500

Aluminum tubing will gall quite easily (same as steel under pressure)
without lubrication. The particles were most likely from the direct contact
of the metals under pressure when they were telescoped without any
lubrication. Texas Towers does not make their tubing. It comes from
aluminum mills and should conform to industry standards for drawn tubing.
It is listed in their ads as 6063-T832, which should be good for most
amateur antenna uses.
The ability to be used for different applications is normally more dependent
on wall thickness, the alloys used in the aluminum, and the resulting
temper. I suspect the reason that TT did not want you to use it for a mast
is that it is thin wall tubing and will collapse under high loading as would
be encountered in most mast applications. I have purchase aluminum mast
material from Texas Towers but it was 2.00 inch diameter and 0.25 in wall
thickness. Great for short masts (for a 2 element 5 band Quad), but again
depends on the loading and it is up to you to calculate this. I don't
believe I would blame it on Quality Control, rather on mis-application of
the material you bought. Aircraft allows (2024, 6061, etc) are much more
expensive new than the commercial alloys.
-----Original Message-----
From: [email protected]
[mailto:[email protected]]On Behalf Of Jim Hill
Sent: Monday, August 26, 2002 12:39 AM
To: [email protected]
Subject: [Antennas] Texas Towers Aluminum Tubing, A Warning.
Their drawn aluminum tubing telescopes but the tolerances are tight.
Imperfections or particles can cause the tubing to jam, preventing it from
telescoping further or taken apart.
I purchased a Butternut/Bencher HF2V, but the bottom section was too short
for a chimney mount. Butternut increased the strength by using two
telescoped tubes, so I purchased two 6' Texas Towers tube sections of the
same diameters. When I telescoped them, I noticed it took more and more
force as I continued to insert the inner tube. I decided to remove the
inner tube and inspect the surfaces, but as I attempted to separate them
difficulty continued to increase and the tubing finally jammed. I cut off
the remaining tube and carefully checked the outer surface. I could feel
some scratches, so I sanded it with 600 grit sandpaper, cleaned it with
paint thinner, lubricated it, and inserted it in the other end. I also
filed the ends to remove any burrs.
I'm not sure what happened. Were there particles inside the larger tube, or
upset metal caused by small surface scratches? The problem reminded me of
copper pipe fittings jamming when put together.
I contacted Texas Towers a few months earlier about using their tubing for
temporary vertical antenna masts. They said "absolutely not", and I now
know why.
I had no problems with the Bencher bottom section, but it was much shorter.
Jim
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