Date: Sat, 9 May 2020 16:53:05 -0700
From: Grant Saviers <grants2@pacbell.net>
To: towertalk@contesting.com
Subject: Re: [TowerTalk] Noob question re: Thrust Bearings
<One alternative often
<used is a cam locking collar or split collar and some use pillow
<bearings made to do that.
## The peer brand thrust bearings, with their eccentric
locking collars work superb, and are used on UST tower.
The collars will lock in either CW...or CCW. They provide
a hole on each end, so a drift punch + hammer is used to
lock the eccentric collar is
<If two thrust bearings are on a shaft and the loading on each one
<becomes indeterminate. So it is never done in machines. So ideally the
<rotator should have to have no thrust load as mentioned. Or if it is
<intended, you won't know what it is. However, once the rotator clamps
<are tightened there will be something happening when the wind blows, the
<tower and mast bend, or the temperature changes, and the top "thrust
<bearing" wears. What??
## two thrust bearings are easily used on a UST or other brand
tower. The trick is, the lower bearing does not have its eccentric
collar locked down...or grub screws. Then NO binding will result.
<Then consider the well regarded US Tower crank-ups use a pipe sleeve as
<the top bearing. Zero thrust capacity. Works well. Also, doesn't need
<separate mast tilt restraints when removing a rotator. Mast axial
<support when servicing a rotator is the only reason IMO to have a thrust
<capable bearing on the mast. A muffler clamp is cheaper.
### That pipe sleeve + double plate arrangement used at the
very top of UST towers is super.
<My choice is a UV resistant UHMW radial top bearings for low cost, no
<maintenance, long life, and low friction. A 6x6x4" thick block ($47) is
<what I made for the 3" mast radial bearing with 500# loading. In
<perfect condition after 6 years. Some use stacked HDPE cutting boards,
<but not UV resistant unless painted.
<Grant KZ1W
## Where did u get 4 inch thick, UV resistant UHMW ??
The thickest we have here in town is 1 inch thick.
Jim VE7RF
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