Doug has a question:
----- Original Message -----
Would either of you gentlemen please provide for me the instructions from Rohn
that states that their TB-3 thrust bearings are to be run dry. I know that they
are sold dry. I am looking for facts from Rohn that say that these bearings
should not be lubricated. I am not interested in any information except from
> -----Original Message-----
>I use White Lithium grease. Some rotator manufacturers are using it
>now. For thrust bearings...It all depends. ROHN says to run theirs dry.
#1. I do know that my TB-3 has been in the air since 1991, unlubed, and is
still going strong.
#2. I seem to remember that there was a rather limited instruction sheet with
the new bearing that said don't lube, but I'll be dipped if I can find it in my
#3. The fact that it was built WITHOUT a grease fitting, and would have to be
removed from the tower and disassembled to grease it says volumes in my book.
#4. The archives show a couple of entries from YEARS ago saying not to lube the
bearings. They weren't designed to be lubed. One of them is from Steve, K7LXC,
who should know if ANYONE does:
In a message dated 97-01-12, you write:
>Since this is an open design for a bearing and it's
>turning slow, one would think it shouldn't need any
>lube. Right or wrong?
The LXC Prime Directive for tower and antenna projects is to "do what the
manufacturer says". The corollary to that is "don't do what they don't tell
you". In other words, Rohn didn't say to lubricate the TB-3 so you shouldn't.
Since it only turns one RPM, there's not much that is going to happen to it
during normal use.
Lubricating it will actually cause premature failure because the grease will
hold onto any contaminants that are blown through in the wind (dust, rain,
etc.). The same is true for crankup cables: do not use a grease on them. There
are special lightweight cable lubricants that you should use that will soak
into the cables without attracting contaminants. In the case of Rohn thrust
bearings, leave 'um alone. And like Rod, N4SI, says, if in doubt - throw it
away and get a new one.
I hope this helps.
Good luck with whatever project you have going.
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