Re: [TowerTalk] Thrust Bearing...

[K8RI <K8RI-on-TowerTalk@tm.net>]

On 1/6/2013 11:34 PM, Jim Lux wrote:
> On 1/6/13 8:02 PM, Grant Saviers wrote:
> > My 2 cents, having two HDX589s and a TMM433.
> >
> > I don't think you need a thrust bearing, if your tower has the welded in
> > sleeve for a 2" mast. I think this is standard on all the current UST
> > crank-ups.
> >
> > The sleeve will handle side loads well beyond the TX438 rated wind load
> > and your rotator will handle the weight load.
> >
> > I had a TB3 on 85' of Rohn 25 a while ago, and it failed.  If you don't
> > have a sleeve and need a bearing to handle side (radial) loads then I
> > think boring a mast sized hole in a top plate of 2" thick MDS Nylon
> > (Nylatron GS) or UHMW is a better approach.  A polymer sleeve bearing
> > will last a long time at the antenna rotational speeds and loads and
> > requires no maintenance.  Both materials are UV sensitive, but not much
> > of a worry in 2" thickness, or just paint them.  I've found remnants on
> > ebay at good prices.
>
> White poly cutting boards. Stack em up, run the hole saw through them,
> and you've got a great low friction, low speed *radial load* bearing
> (which is really what you want, anyway). (actually, I suspect a single
> layer is good enough)
With a smooth, well fitting mast I'd expect a single board/layer would 
support more than the tower we've been talking about.
73

Roger  (K8RI)

> http://www.target.com/p/kitchen-3-pc-cutting-board-set/-/A-510239#prodSlot=medium_1_3
>
>
> http://www.target.com/p/chefmate-poly-cutting-board-white-14x17/-/A-10219387#prodSlot=medium_1_16
>
>
>
> http://www.walmart.com/catalog/product.do?product_id=13397991&findingMethod=rr
>
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