Hey Peter,

Ever used food grade oil for tapping? I'm thinking colza oil(rapeseed oil), really popular here instead of sunflower oil but since its used in machinery too, I got curious if I could use it for tapping. I have a 1.4404 stainless steel plates and need to tap M4 threads. It's a part of a custom humidifier and since I'll be breathing in whatever is on the surface I'd love to avoid anything that's not biocompatible. The tap is a 3 piece.