Thank you for entering in my post

I have a 20 mill cutter with 3 tips and radial screws, and one of these tip gets loose when it's machining

I remember, when I had my apprentship, we used to use a sort of copper paste on the thread of the screw

I know that this 20 mill cutter with 3 tips is not the best, however I was wandering if this copper past would help to keep the tips, or if there is something-else that would help

If yes, how does it work?

Any information according this matter will be very appreciative

Thank you in advance for your help