[TowerTalk] Response from Rohn re: TB3 and TB4 thrust bearings.

[Patrick Greenlee]

In some instances not lubricating bearings is the right thing to do.  For 
example, in our environment which is sometimes windy/dusty and becoming more 
so due to extreme drought, I was cautioned to not lubricate the bearings in 
the roller wheels distributed along each side of my automatic raise/lower 
garage doors.  Ditto for my 14 x 14 ft roll-up equipment parking barn doors 
and the various laterally opening doors of my hay barn as well.  To do so 
invites the collection of abrasive grit and short MTBF lifetimes.  Other 
than the dirt/grit issue of bearings that are not sealed I know of no reason 
to not lubricate bearings that can be lubricated.  I am also not a 
mechanical engineer but have a good friend who has a MS in mech eng from 
UCLA and 35 years hands-on experience.  I will pose this issue to him and 
report back,  Sealed bearings would be nice as the total revolutions 
accumulated over the life of a rotor system is small compared to many other 
standard applications.

A  DIY bearing weather cover with custom molded silicone rubber seals would 
keep out water and debris.  Mold release spray or even a thin layer of 
lubricating grease will keep silicone rubber from adhering where you want it 
to slip. A good thick bead of silicone rubber between a DIY bearing cover 
and a fixed plate (greased or sprayed with mold release) will make a 
silicone rubber seal to keep put water and debris. I haven't done this to 
antenna tower thrust bearings but have done so in other applications and it 
worked well and lasted a ling time (several years.)

Patrick AF5CK

-----Original Message----- 
From: Jim Thomson
Sent: Monday, March 04, 2013 9:47 AM
To: towertalk at contesting.com
Subject: [TowerTalk] Response from Rohn re: TB3 and TB4 thrust bearings.

  A friend of mine asked Rohn about the tb3 and tb4 bearings.   I had a
pair of TB-4 bearings on my old tower setup.  I now use peer brand
bearings on the USt HDX-689..with locking collars.

Jim   VE7RF

.......................................................................................................



Hi,

I have a question about the TB3 and TB4 thrust bearings. The bearings
are shipped dry but there is no instruction regarding lubrication. Should
these bearings be lubricated, either grease or oil or left unlubricated, or 
it
is left to the owners discretion? What is Rohn's instruction here?
Thanks,


XXXX




XXXX

It is up to the user whether they want to use lubricant or not. We do
not feel that it is necessary. We have some that have been installed at
our location for a number of years without lubricant, with no issues.

Thanks,
Tim Rohn
309-566-3037
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