"Joe AutoDrill" wrote in message
...
One of our customers with a special three spindle drilling head is having
some problems.

How are the bearings failing, Joe? Are the balls spalling, or the races, or
is it a case of the races getting worn?

It sounds like it's a specific-load issue, rather than a finish or precision
issue, so better-quality steel bearings probably won't help. You have to get
the specific load down to something acceptable. Plain bearings will do it,
but maybe there's some kind of tapered roller that will fit. That would
reduce the specific load a great deal.

--
Ed Huntress