Quote Originally Posted by justgary View Post
The main spindle bearings just might be good up to 7K RPM, but they definitely won't last as long as they do below that.
Well, yes, bearing life is inversely exponentially something-or-other proportional to speed, but it depends on the meaning of "as long"...

Just Gary, remember this post by Greg Jackson. In it he says
By our estimate the spindle design is fine for anything up to 7000 RPM. Taking it higher is certainly possible, but will lead to shorter bearing life.
and
We agree with one of the posts, 180F to 200F is a fine range for the spindle bearings at top speed.
To me that sounded like 7 krpm was an acceptable running speed. Maybe I'm being wishful, but if the bearing life at that speed is equal to the useful life of the machine otherwise, "as long" is long enough...

Randy