On Mon, 30 Nov 2009 09:59:17 -0500, "Ed Huntress"
wrote:


"Ned Simmons" wrote in message
.. .



This doesn't make sense to me. If a high ABEC class bearing will
outlast a lower class bearing under ideal conditions, what's the
mechanism that will cause it to fail sooner in a less than ideal
installation?

--
Ned Simmons

There's nothing much to "crush." A given amount of displacement of one race
relative to the other can produce a substantially higher preload in a
higher-class bearing. The difference may be slight, but small variations in
the percentage of yield strength that a bearing is subject to will produce
large variations in its fatigue life -- in other words, the time it takes
for the bearing balls or the race to spall.

Right. But I understood you to say that the imperfections on the
contact surfaces of a low class bearing will cause it to fail earlier
than a high class bearing when they are both properly mounted. On the
other hand, you also seem to be saying that those imperfections are
*protecting* the low class bearing in a poor mounting.

If you imagine looking at only a very small patch on the bearing race,
there's no way to tell whether the bearing is mounted properly or not,
all you can determine is the contact pressure as a ball passes. If
there are imperfections in the surface of the low class bearing's
race, there will be local peaks in the contact stress, regardless of
the how the bearing is mounted.

Re the temperature compensation business, I was looking thru some of
my references and found this:
http://tinyurl.com/ya7hvm4

There's about a half page missing, but the jist of it is there.

--
Ned Simmons