[Antennas] Texas Towers Aluminum Tubing, A Warning.

[Jim Hill]

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