[TowerTalk] Noob question re: Thrust Bearings

[Grant Saviers]

Jim,

mcmaster.com stocks black UHMW to 5 inches thick in 6x6 and larger 
sizes.  I've also found it on ebay.

Grant KZ1W

On 5/10/2020 09:58, Jim Thomson wrote:
> Date: Sat, 9 May 2020 16:53:05 -0700
> From: Grant Saviers <grants2 at pacbell.net>
> To: towertalk at 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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