Nakamura-Tome Spindle Repair
Nakamura-Tome TMC-15 spindle, 4500 RPM, grease bearing lubrication, belt drive
This CNC turning center came to us complete with the cast housing and the hydraulic collet actuator. Every assembly bolt was only finger-tight, the spindle was full of coolant and the bearing grease was washed out. We tested the collet actuator which functioned properly, but unfortunately it was missing several o-rings which also contributed to the contamination. Our dimensional inspection established that the lathe taper OD & face had excessive runout, and that the front housing ID was oversized by 5 times ISO.
We recommended green grinding, hard chromium plating & finish grinding the lathe taper and the housing ID, but our customer declined the latter. So we performed the G/P/G of the lathe taper and kiss ground the face, but we did not address the housing ID. Once the approved dimensional work was completed on our Kellenberger universal cylindrical grinder, we proceeded to replace the bearings, pulley nut, o-rings & bolts. When final assembly was complete, we ran the spindle to break in the new bearing grease while checking the vibration & heat signature. Once we balanced the spindle, we were ready to ship it back to our customer. With any luck, they will get another 20 years use out of it.