----- Original Message -----
From: "Pat Chiles" <chilesp@adelphia.net>
To: <towertalk@contesting.com>
Sent: Thursday, September 30, 2004 10:44 AM
Subject: [TowerTalk] Three Questions for HDX-555 Tower Project
Hey guys could I tap you vast knowledge to to get some comments on the
following.
1. How hard is it to drill chromolly?
With good quality high speed drill bits, drill a 1/16" hole first, then
slowly progress upwards in size until you reach the diameter you need. That
shouldn't be a problem using this multiple drilling. Use some oil when
drilling. A variable speed drill motor running slow will also be better than
a fixed speed drill motor. If you see smoke, your going too fast.
2. Comments from hams with experience as to whether or not the raising
fixture will lift the tower from horizontal to verticle with a 21 ft
chromolly mast (2 in., 140 lbs), a TH7, and a XM240 installed without the
tower crashing back to mother earth?
The raising fixture is designed to handle the tower only. It will never get
your system up off the ground by itself. I accomplished what you wish to do
a number of years back with my Tri-Ex LM-470 and raising fixture by using a
lift truck with the forks under the tower, from the side, about five feet
out from the base, and cranked the winch while using the hydraulic power of
the lift truck to raise the forks, which easily slid up the surface of the
two (hinged)outer tower legs. Once you get past the 50-60 degree point, and
the forks are all the way up as far as they will go, the winch and raising
fixture can easily do the rest. Its the initial shearing type force of the
hinge bolts that is so great, even the tower itself is difficult to start
lifting at the starting (near horizontal) point. Fortunately I had an
industrial area just a half block away from where I was living at that time
and befriended one of the superintendents there and he lent me his lift
truck for gratis. I returned it along with a case of beer and thought that
to be a win-win situation.
3. Suggestions for keeping the antennas from slipping on the mast other
than pinning?
Drill and pin the antenna boom to mast clamps to the mast, yes, even the
Hygain clamps. On the rotator to the mast, after everything is in position
and tight, drill a 3/16" clearance hole for some brass 10-32 or 10-24
threaded rod, available at most well equipped hardware stores. Install this
threaded rod with double nuts on both sides and it will act like a shear pin
before the rotator gets stripped. It's much easier to put the mast with
antennas back in position than any or all of the antennas. In addition, you
now have a "alignment hole" and the sheared brass in the mast will easily
come out with a 1/8" drift punch. Tap a new piece in and double nut it and
then tighten the rotor clamping mechanism and you're done! 73, -=Rog-K9RB=-
Thanks, Pat, K8PC
_______________________________________________
_______________________________________________
See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless Weather
Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any questions
and ask for Sherman, W2FLA.
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