[TowerTalk] clamp on thrust bearing?

[Grant Saviers]

Jorge,

Do you really need a thrust bearing or would a radial only bearing do 
the job?  Most rotators will handle the thrust load  (mast plus antenna 
weight) ok, but need a radial bearing at the tower top for lateral support.

If radial only is ok, then some thick plastic (or several pieces at 
least 1/2" thick), with a hole bored to the mast outside diameter plus 
about 0.030", drill holes for the mounting bolts, saw the plate in half 
thru the mast hole and bolt it in place.  Black UHMW is usually fairly 
UV proof, very slippery, cheap and available to several inches thick.  I 
use 4" thick, but that is probably overkill.  Some use oak or other 
hardwood (teak?)  but not sure how long that will last, especially in 
your climate.

I'm not aware of any split real thrust bearings but split shaft collars 
are available http://www.mcmaster.com/#split-shaft-collars/=14jxj7i   
Not sure how well that would work with a split joint on the collar and 
one on the plastic radial bearing.

IMO, many commercial "thrust" bearings for towers are not very good 
thrust or radial bearings, need regular lubrication, and are prone to 
failure as you have experienced.

Grant KZ1W



On 10/11/2016 11:48 AM, Jorge Diez - CX6VM wrote:
> Hello
>
> do you know about a clamp on thrust bearing?
>
> I need to replace a broken one on top of the tower and i dont want to
> remove 2 big antennas I have on the mast
>