In a message dated 9/12/01 1:14:41 AM Pacific Daylight Time, na6t@mcn.org
writes:
> I got 2@ rohn TB-3 bearings and found that the couldn't be lubed. NO
> grease fittings. I guess this is 'extra care in engineering". So I
> dis-assembled the bearing, drilled vertically down from the top cover to
> the race and then drilled at a 90 degree angle to the first hole and
> installed a zerk fitting, and then plugged the original hole from the top.
First, you copied the ENTIRE DIGEST in this post. That was totally
unnecessary. Please only copy the germane part - NOT the whole thing.
Your modification of the Rohn bearing was also unnecessary as well as the
wrong thing to do. The Rohn TB's are designed to be non-lubricated. Since the
bearings are not sealed, any airborne grit or dirt will be attracted to the
grease in your bearing and will contribute to premature failure.
>
> Now I've got a pretty good bearing and it can be greased.
The whole thing only turns at one rpm - what advantage would there be in
lubricating it? The major failure mode of the Rohn TB's seems to be damage to
the aluminum races - not rust. Since the races are aluminum, they don't rust.
The ball bearings can get some surface rust but that typically isn't fatal.
Corollary to the LXC Prime Directive:"DID the manufacturer tell you to do
this?".
Cheers, Steve K7LXC
Tower Tech
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