[TowerTalk] Purpose of Thrust Bearing

[Mike]

Brian Machesney wrote:
> I'm trying to clear up a point of my own confusion and/or ignorance w.r.t.
> "thrust bearings."
>
> I used to think that the "thrust" taken up by the bearing, e.g. when
> supporting an antenna mast, was a vertical force. I have read a lot on this
> reflector recently that contradicted that belief. In searching McMaster-Carr
> for a bearing to take a vertical load, I find that they describe a "thrust
> bearing" as being designed to, "Support loads parallel to their axis of
> rotation."
>
> This sure sounds to me like it's meant to support the weight of a mast and
> antennas - a vertical force when we mount a thrust bearing in the hole at
> the top of a tower or on an "accessory shelf."
>
> Which is it?
>
> 73 -- Brian -- K1LI
It's the McMaster-Carr definition.
Some people describe using two bearings, one above the other,  to 
prevent lateral forces from acting on a rotor (like a pry bar on a 
fulcrum), but that's not the designed purpose.

73, Mike NF4L