What kind of lube should I consider using for a milling machine gearcase? The existing lube is about ISO68 but the machine is an import and I have no idea what the oil seals are made of or bearing info. The milling machine is an import without lube info in the manual. The machine sees light duty. Max rpm is 1800. Any pointers appreciated.

Mike,

ISO VG 68 Gear oil meeting AGMA 2 or Cincinatti Milacron P 59 or DIN 51517 Part 3 would be appropriate.

From the popular brands you can choose from Mobilgear 68, Shell Omala 68 or Castrol Alpha SP 68 etc. Unless otherwise stated these grades will be fortified with additives that will not affect seals.

For the slideway or carriage movement Cincinatti P 53 is popular. It is available in ISO VG 32 or VG 68 viscosities. This lubricants are compounded to prevent stick & slip of the slideway. Castrol Magna GC 32 and Magna BD 68 were popular grades in the 90's.

Hussam Adeni

Thanks for the answer. That helps a lot. I heard on another site that someone with roughly the same issue saw excess foaming with the Castrol which no one could explain. Could this be a reaction with the previous unknown gear oil? Should I do a brief run in with a light mineral oil before filling with the new oil?

Mike,

Foaming is largely due to two reasons 1. Aeration and 2. Water. Flushing is a good idea during any change over, installtion or commissioning.

Hussam Adeni

Thanks, again. We'll give it a try.
Mike