Quote Originally Posted by G0G90 View Post
Roll tapping (obviously) is a high pressure process.

By changing your coolant, you've lost lubricity for high pressure cutting.
I'd check with your supplier to see if there's an additive available. Otherwise, go back to your water-based (assuming it was synthetic or semi-synthetic)
Well, that I cannot do. The one I was using (Ecocool S761, Fuchs) was killing everything, rust was all over the machine. That is why we have gotten rid of it.
Any suggestion about good cutting oil??

BTW - Thank for an answer G0G90 :cheers: