Studer S-20 Spindle repair
Studor S-20 Hydrostatic, Belt Drive, 910 rpm
We sometimes receive spindles with the drive motors. We always like to run the spindle and motor to test run and evaluate before breaking down. When we received this Studor spindle we also received the motor as it is a whole unit. The spindle was seized however the motor tested and ran fine. The customer was made aware that we would only need to rebuild the spindle. The incoming analysis showed that the drive pulley bearings were seized due to coolant contamination. The drive belt was worn, likely caused from the pulley bearings being seized. The main spindle shaft OD seal surface grooved from seal wear, the ID taper was worn from use and had 6 microns of run out. We also found the bronze bushing for head swivel was egged.
We recommended grind, chrome plate and finish grind the main spindle shaft OD seal surface, kiss grind the ID taper, manufacture a new guide bushing, spacer and replace bearings, seals, o-rings, snap ring, belt and oil sight glass. The customer approved the scope of work. The shaft was put on our Kellenberger grinder for the dimensional work needed on the shaft. Our machining department manufactured the new guide bushing and spacer. Once all items were finished and received we assembled the spindle and balanced. All critical quality control testing was taken. The spindle and motor passed and was boxed up in our manufactured crates.
The customer received and installed the unit and is happy that we were able to save them money by testing each unit before breaking down.