[TowerTalk] thrust Bearing

K9MA k9ma at sdellington.us
Sat Dec 26 13:45:42 EST 2020

OK, technically the Rohn TB3 is a radial support bearing, with vertical 
races. That's just not what Rohn calls it.

Scott K9MA

On 12/26/2020 12:34 PM, Wilson Lamb wrote:
> 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,
> Wilson
> https://itstillruns.com/types-universal-joints-7456638.html
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Scott  K9MA

k9ma at sdellington.us

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