[TowerTalk] thrust Bearing

Wilson Lamb infomet at embarqmail.com
Sat Dec 26 13:34:54 EST 2020

Why can't we get the terminology right?
THRUST BEARINGS take THRUST loads, along the axis of a shaft, like a ships propeller shaft.
I don't know if there's a specific name for radial support bearings, but they are the one's we have all around us, like in your car engine or BBQ spit.
Yes, a thrust bearing will take up some radial load, but it usually isn't meant to. 
There are combination bearings, like the tapered roller bearings in your car wheel.
A radial support bearing, if not built as a combination, won't be happy with much thrust load on it.
Think of a ball bearing on its side.  Thrust is driving the balls between the races, like a wedge, which will eat the races out on one side and eventually drive the balls out the side, if the outer race doesn't snap first.
The Rohn sleeve won't take any axial load at all.
To have a thrust bearing at the top of your tower you must have robust setscrews driven into the side of the mast very firmly, ideally in dimples.
The screws may be in the top of the bearing assembly or in a collar around the mast.
The screws must transfer the whole thrust load to the bearing's top race, then the balls/rollers transfer the load to the bottom race which transfers it to the tower.
Yes, many thrust bearings use balls, but the races are horizontal.   Two plates with marbles between would be way to think of them.
I KNOW this is all old hat and obvious, but I've been pained by the misnaming on here for at least 15 years.
Now it's off my chest...HAPPY NEW YEAR,


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