> After nearly 30 years of holding up my TH7 and D40, the thrust bearing was
>pretty rough. The T2X never had any trouble turning it, but I took it apart to
>see what was going on. I found the surfaces of the two aluminum pieces deeply
>indented by the ball bearings. It's scrap metal now, but I wonder if the long
>periods I left the antenna in one position might have made things worse. Would
>it have helped to just turn it once a week or so? Or is such failure
>inevitable?
Ok, please disregard any advice about lubing the Rohn thrust bearing. This
TB should not be lubricated as any grease in the races will accumulate dirt and
grit and accelerate its wear and demise.
Yes, leaving it in the same heading is the primary cause of the bearings
being hammered into the aluminum races. Since most of the time it doesn't
matter which way the antennas are pointing just leave it where it was and
spread out the wear. (I'm not going to mention which way the antennas should be
parked - that's the subject of some speculation.) Since the hammering primarily
happens on the side opposite the wind direction, you could leave it 180 degrees
from normal parking also.
And having the rotator take the weight of the array instead of the TB is a
good idea. It'll help seat the rotator bearings and alleviate most of the wear
on the TB - both good ideas. IMO the use of a TB is for vertical forces is
highly overrated. The TB, bushing, piece of wood, whatever is to capture the
mast and keep it from moving horizontally.
Cheers,Steve K7LXCTOWER TECH -Professional tower services for commercial
and amateur
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