[TowerTalk] Lift Mast to Replace Rotator

[Grant Saviers]

My 2c, again

In terms of number installed I think most rotators have angular contact 
ball bearings. HyGain, Yaesu, & prop pitch all are angular bearings, 
which are the only ball bearings designed for both radial and thrust 
loads.  They should to be loaded to keep the balls in correct position 
in the grooves. (but die cast aluminum races and steel balls are not 
much of a bearing so nobody notices).

K7NV advises the entire thrust load be on the prop pitch motor.

The pipe sleeve on my HDX589 is the simplest radial bearing and has the 
further advantage that the mast can't tilt when the mast is raised to 
service the rotator.  So if the vertical load is less than the spec (eg 
440# for a Yaesu G1000), use a sleeve radial bearing of plastic and 
never ever have to lube it or replace a worn out "thrust bearing" or one 
seized up from rust.

Orion is an exception that uses a real thrust bearing and deep groove 
ball bearing combo which is spec'd for thrust loads up to 1800#.  Will 
your tower handle that?  SPID rotators also use oversize deep groove 
bearings so preload isn't needed.  So each rotator design has different 
properties.

The only add-on sold as a "thrust bearing" that I think has competent 
engineering is the angular contact one from DX Engineering.

Grant KZ1W





On 12/27/2019 04:38, David Gilbert wrote:
> 
> Another guy just said the same thing you did, and I'm not sure that is 
> universally a good idea.  I expect Steve to eventually weigh in here 
> with more authority on the subject, but from what I understand some 
> rotators WANT to have some vertical weight on them to keep the bearings 
> properly aligned.  Free floating bearings aren't always a good idea.
> 
> Dave   AB7E
> 
> 
> 
> On 12/26/2019 5:46 PM, W3YY wrote:
>> John -
>>
>> Next time install two bearings that provide both lateral and thrust 
>> support.
>> And then install the mast so there is no weight on the rotor.  Then 
>> you can
>> easily remove and replace the rotor.
>>
>> 73, Bob - W3YY
>>
> 
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