[TowerTalk] Re: Thrust bearing

[Jerry Keller]

Chuck, N4NM raises the question whether taking all the vertical weight load off the rotator will have some adverse effect on it, due to failure to "preload" the bearings, etc. 
I dunno. 
But even though I tried to take "all" the weight on the thrust bearing, since I tightened up the whole thing in the horizontal position I'm pretty sure at least some load is transferred to the rotator. 
73,  Jerry K3BZ
  ----- Original Message ----- 
  From: K4FJ at aol.com 
  To: towertalk at contesting.com 
  Sent: Thursday, July 22, 2004 4:21 PM
  Subject: Re: [TowerTalk] Re: Thrust bearing



  In a message dated 7/22/2004 3:50:29 PM Eastern Standard Time,  k3bz at arrl.net 
  writes:

  I use  two thrust bearings, one at the top and one a couple of feet down the 
  mast.  The rotator is a couple of feet below the bottom TB. The top TB is 
  merely a  guide; the bottom TB supports all (or nearly all) the weight of the mast 
  and  antennas via two opposing "double-saddled" muffler clamps on the mast. 
  The  mast doesn't actually bear much on the rotator... the rotator merely grips 
  the  mast and turns it. I figure the less weight that bears on the rotator, 
  the  longer it will last.... and TB's are cheaper than rotators!  I do have  
  the mast pinned to the rotator, however, as the Yaesu rotator provides for  
  pinning. 
  This is my first tower, but this arrangement seems to work A-OK  for me. I've 
  had no slipping or other problems with it.

  73,  Jerry  K3BZ



  Jerry's approach using two bearings (or a thrust bearing and guide) before  
  the mast gets to the rotator is the preferred method.  You will realize it  the 
  first time you want to change out a broken rotator.  However, it you  choose 
  to use a Rohn top section with the snorkel top, you can get away with a  
  single thrust bearing on a plate above the rotor.  The snorkel is your  guide.  A 
  bit harder to get to the antenna attachment point but not  bad.
   
  73, Steve
   
  _______________________________________________

  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.

  _______________________________________________
  TowerTalk mailing list
  TowerTalk at contesting.com
  http://lists.contesting.com/mailman/listinfo/towertalk