Originally Posted by
edn
Page 56 of "Timken Super Precision Bearings for Machine tool applications" says:
The use of “low-torque” greases (or synthetic greases) can be
considered for rib speeds over 13 m/s (2560 fpm), up to maximum
of 25 m/s (4920 fpm). Experience has shown that stabilized
temperatures, around 15° C to 20° C (27° F to 36° F) above ambient,
can be obtained at the maximum permissible speed.
....
When using synthetic greases, the limiting factor is the "lubrication
for life” concept (without re-greasing). Depending on load and
speed conditions, the grease life will typically be limited to 5000
to 8000 hours.
As I mentioned earlier, when new spindle arrives I will put headstock apart and document it's condition if anyone is interested.
Ed