[TowerTalk] Purpose of Thrust Bearing

[Al Williams]

I hope that some there will come a posting in simple terms about the purpose 
of a thrust bearing?

It seems to me that the "axis of rotation" for a mast mounted thrust bearing 
is vertical, thus the design is to support
loads around the mast that are not equalized?

However an jet engine is rated in thrust which is in line with the motion of 
the air?

These two are in conflict, whats wrong?

k7puc


--- Original Message ----- 
From: "Mike" <nf4l_NO_SPAM at nf4l.com>
To: "Brian Machesney" <nekvtster at gmail.com>
Cc: <towertalk at contesting.com>
Sent: Monday, June 01, 2009 3:41 PM
Subject: Re: [TowerTalk] Purpose of Thrust Bearing


> 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
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