"Ned Simmons" wrote in message
...
On Fri, 13 May 2011 21:52:15 -0400, GeoLane at PTD dot NET GeoLane at
PTD dot NET wrote:


I wouldn't pack the bearings with any grease containing moly, unless
it's specifically recommended for ball bearings. Moly lubes are
generally called for in heavily loaded plain bearings and not
recommended for small rolling bearings.

Why isn't it recommended?

RWL

MoS2 is a solid lubricant, like graphite. My understanding, and I'm no
expert, is that it can pack into larger particles in a rolling
bearing, and cause problems in small bearings with tight clearances.
There are moly greases recommended for ball and roller bearings, but I
think you'll find their use is typically limited to larger bearings in
severe service.

I do have first-hand experience with moly oxides (not MoS2, but of
similar consistency) packing in linear ball bearings to the point that
the balls stop rolling.

--
Ned Simmons

ISTR a NASA report from way back showing graphite building up in this way
and taking up clearances in rolling element bearings. But really, if your
application is cool enough that mineral oil grease is OK, moly isn't going
to give you any benefit.

Moly greases are used in CV joints where there is rather limited rolling,
and the forces are very large (so I'd expect any moly buildup just to
extrude).