[Terrible Terry]

Newbie here and only have had a Fadal 4020 for 3-4 months. I only have single phase power and I have been running my vmc on a rotary phase converter with no apparent problems. The belts started squealing lately so I removed the spindle cover to discover lots of metal shavings stuck everywhere and some signs of oil possibly my belt squeal. Spent a day disassembling and cleaning so I could track down any oil leaks. Found a way oil leak and a belt tensioner cylinder shaft seal leak. The belts were well work and cracked so I order a set of new belts. After the belts were installed and I did a slow spindle run up I discovered a bumping and thumping from the spindle motor most apparent at low rpms and I just think I never noticed it before. You can feel the thumping with you hand placed on the motor and Im thinking it acts like mini power bumps either on or off. At higher rpms you can barely feel the pulsing and you cant hear it like you can at the low rpms.This is a DC machine with a Baldor vfd by the way. I assume this motor has brushes, could this be the problem? Would appreciate any and all help as I have zero cnc experience until I bought this mill.

[grantlewes]

Id like to bump this even it it's almost 3 years ago!