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.
Grant KZ1W
On 1/6/2013 7:20 PM, Stan Stockton wrote:
My opinion, unless you are putting up something bigger than what a TX-438 tower
is rated to handle, is that it is a waste of about a hundred bucks to use
anything more expensive than a four bolt flange bearing with a clamp on the
mast resting on the bearing collar so you are not relying on set screws. You
can spend $160 for a TB-3 or you can spend $30-40 on something that will do the
job just fine. That has been my experience anyway.
73...Stan, K5GO
Sent from my iPad
On Jan 6, 2013, at 11:40 AM, Dave Cole <dave@nk7z.net> wrote:
Hi,
I am looking for a general education on Thrust Bearings... My tower,
(TX-438), did not come with one, and I am looking to get one...
Are they rated by size, or is each bearing pretty well made for each
tower?
--
73's and Thanks,
Dave
http://www.nk7z.net for equipment reviews, propagation, and more...
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