A little history lesson... I apologize if it's a TT dupe.
(Telex) Hy-Gain got into the tower business in the early eighties
when a former Tri-Ex sales manager went to work for them in
Nebraska. The HG-70HD is in the same general class of tower as the
Tri-Ex LM-470-- not identical, but similar.
I think it's well known that Karl, of Tashjian Towers today, was an
engineer for many years at Tri-Ex, back in the day (Karl is not the
former Tri-Ex employee I mentioned above). Tashjian builds an
updated, modern LM-470 today and these are excellent towers.
If I needed to rebuild an HG-70 tower, I would contact Karl at
Tashjian. But first, without ambiguity, measure the diameter of the
cable(s), the diameter and maximum thickness of the sheaves; and the
diameter and lengths of the sheave bolts or pins. Note details such
as whether the pin is a flathead, sockethead screw, and so forth. I
would also note the exact clearance available between pairs of
sheave-mounting plates. Send the list of what you want to buy, along
with the measured data (don't guess) to Karl and let him tell you if
his sheaves and some of his spare parts will do the job for
you. Except for the sheaves themselves, most of what you will need
is also available as standard industrial grade hardware.
As to Nylon sheaves, on crankup towers... what are the magical
properties of them that would make a tower owner consider
substituting them in place of OEM steel or machined aluminum
sheaves? I don't see Nylon sheaves on the UST or Tri-Ex or Tashjian
towers I have seen. Would someone on this mail list install Nylon
wheels on his car, if the OEM steel wheels were to wear out?
Just wondering.
--Glenn K6NA
PS- To Nick's question re thrust bearing: Last year an HG-54 owner
and I tried to find a bearing to match the Hy-Gain bolt pattern on
his top-plate. Eventually he just settled on a decent Chinese
bearing available on the Internet ($45 range), and I drilled new
holes in the tower top plate.
At 04:40 AM 8/24/2013, you wrote:
I have a Hy-Gain HG-70HD tower, new in 1985. I'm in the process of
refurbishing it and would like to replace the cable sheaves and
related hardware as part of the process, but am unable to locate a
source for those items. MFJ still sells the towers but apparently
does not sell the parts and they have not been helpful. Does anyone
have information as to where I can find these parts or sufficient
information that I could have new ones made in advance of
disassembling the tower? I'm also looking for a thrust bearing
assembly for the tower. Any information would be most
appreciated. Thanks for your help.
Nick, K8NAP, goodsonrd@netwalk.com
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