I use Shell Tellus S2M on mine, without any drama ......that I am aware of. My lathe is a Chinese import so not sure what yours actually require, can you ring the lathe manufacturer and see what they suggest, if it is Shell oil what you require then google "Oil Shell distributor", ring one up closest to you and ask them to give you a contact name of one of their retailers. They should have a database of their retailers and what products they have ordered.
Cheers
Ed.