[TowerTalk] thrust Bearing

krgoodwin at comcast.net krgoodwin at comcast.net
Sat Dec 26 15:53:21 EST 2020

THRUST BEARINGS take THRUST loads, along the axis of a shaft, like a ship's
propeller shaft.

Therein lies the problem, you've got the definition of thrust correct but
thrust bearings are not meant for vertical loads along the gravity vector
but loads in the horizontal plane (perpendicular to the gravity vector).
This was the whole point of my original question since I like you assumed
the definition of thrust applied as to how the bearing was to be used on the
tower's top shelf so I loaded all the dead weight on the thrust bearing.  I
used a shim at the bottom of the mast between the mast and the rotator
plate, tightened the thrust bearing's mast clamp bolts, removed the shim and
then tightened the rotator's mast clamp bolts.  The rotator is only required
to apply a torque with all the weight on the thrust bearing.  Wrong again
Kemo sahbee.  My rotator used a wedge brake so there was always a small
rotational slop in holding the beam in place.  Taking all of the vertical
load (dead weight), the thrust bearing's race became severely pitted and
eventually the bearing froze.  Still lost as to why those that sell thrust
bearings can't provide a clear set of instructions but I dream a lot too.
Ken K5RG

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