[TowerTalk] mast bearings (reply de K0FF)

[K0FF]

If there is a top mast tube, then you don't need a 2nd bearing (ALA US
Tower.). If you're using a Type 55 etc. with a flat top plate, use a second
bearing plate. I always put a 2nd bearing on the 2nd plate, but you don't
have to. Sometimes you can make a collar or sleeve out of cedar wood. The
purpose is not to carry weight but to control side thrust, especially when
removing the rotor for repairs.

On my Rohn 55, I use a beacon plate at the top, and cut a hole in it for the
TB4 bearing with a Plasma Torch. Below it is a standard bearing plate with
another TB4 (3").  I am using the APL beacon plate on top because it's very
sturdy (20 pounds) vs the 3 pounds for the BPL bearing top plate.

Don't forget to drill and tap the mast for 1/2" bolt just above the rotor
clamp, and drill the top plate and bearing plate, and notch the rotor plate
for a mast-raising winch.

Geo>K0FF
-----Original Message-----
From: Michael J. O'Connor <kn9t@webtv.net>
To: towertalk@contesting.com <towertalk@contesting.com>
Date: Thursday, June 22, 2000 9:51 PM
Subject: [TowerTalk] mast bearings



In a large hf stacked array with 15 feet out of tower and 10 feet inside
is it necessary for more than one thrust bearing . Would binding become
a problem if one was placed between
top bearing and rotor . 73 KN9T


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