[TowerTalk] Which thruse bearing?

[Jim Lux]

At 02:02 PM 12/12/2006, Floyd Rodgers wrote:
>Trust me guys, the only way you MIGHT save the bearing is to have a 
>flexible low impedance strap connected to the tower and mast. You 
>wouldn't believe the number of bearings I've seen pitted, melted or 
>welded together just from some welder striking an arc on machinery. 
>any current flow will have an effect on the bearing.


That would be my general impression.  The contact area on a typical 
ball bearing is SO tiny that the current density is very high, and 
heating is almost certain.  Once heated, the ball and race hardness 
is changed in that place, and it will wear differently, and once the 
race isn't smooth and the ball isn't round, the bearing is toast.

OTOH, an antenna thrust bearing is such a wide tolerance, low speed 
application, that something like a stamped lazy susan bearing would 
probably work. It's not like you've got some sort of finely balanced 
machine tool running at 10,000 RPM. If it pitted, who'd care. Fusing 
and welding together is another issue.

Jim, W6RMK