I know there are some folks here that have considerable experience with high speed parts and lubricating oils. I anyone has recommendations for oils with properties suitable for high speed bearings, I'd appreciate hearing them.
The spindle speeds in toolpost grinders can range from about 6k to 30k RPM.
I haven't taken them apart to see exactly what types of bearings are used in the spindles, but I would expect them to be high precision ball bearing assemblies. I've seen parts list prices of over $200 each for bearings with ODs of about 1.25".
I presently have two brands, Themac 1/2 HP and Dumore 1/4 HP.