[TowerTalk] Ham Antenna Rotator: The Teardown

[Charles Gallo]

The short answer to why they get fretting is because ball bearings are not really the best answer for intermittent rotary motion, with vibrational loading. It was why a lot of applications stuck with sintered bronze, and today use plastic. I STILL say that this bearing, along with the thrust bearing are the perfect spot for an injection molded engineering plastic bearing

--  
73 de KG2V
Charlie

> On Dec 3, 2018, at 9:44 PM, Grant Saviers <grants2 at pacbell.net> wrote:
> 
> The real HyGain (pre MFJ) would supply a high end grease, about an oz for $15, with anti-fretting properties.  I found it commercially but only in commercial quantity packaging and it was quite expensive.
> 
> I use Superlube 21030 with TFE full synthetic, a tube costs less the $10.  Full synthetic won't dry out or separate like white lithium or other mineral oil plus carrier greases.  A widely available, cheap, and excellent grease with a much wider temperature range than mineral oil greases.  Not overkill.
> 
> If you want the gory details why rotator races get divits
> https://www.machinerylubrication.com/Read/693/fretting-wear
> 
> Grant KZ1W
> 
>> On 12/3/2018 16:06 PM, Bob K6UJ wrote:
>>  Norm's Rotator Service on line says:   "either a white lithium or green emerald.  Under no circumstances should wheel bearing grease or any other grease with fibrous material content be used".
>> As they said, wheel bearing grease is a fibrous grease and should not be used.  There is a large selection of greases that are non fibrous.    There are many (non fibrous) grease lubricants better than Lithium which are rated for more severe service and lower temperatures than the Lithium.  I am planning on using a synthetic grease in my rebuild.  It  will be an overkill for California but I will sleep well at night.  hihi
>> BobK6UJ
>>     On Monday, December 3, 2018, 3:12:40 PM PST, Rod Greene via TowerTalk <towertalk at contesting.com> wrote:
>>     Years ago I remember reading to not use grease on the ball bearings as it just attracts dust and dirt. And, that the design from the factory did not call for grease. Is this correct or should one use a grease on the ball bearings? 73, Rod/w7zrc
>>     On Monday, December 3, 2018, 8:35:44 AM MST, Edward Mccann via TowerTalk <towertalk at contesting.com> wrote:
>>    Interesting article recently noted
>> https://www.electronicdesign.com/analog/ham-antenna-rotator-teardown
>> Ed McCann
>> AG6CX
>> Sent from my iPhone
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