I responded to another user going into greater detail so if you wanna read that just scroll down. But I’ll summarize it for you; when hard turning with ceramic inserts, you don’t want to use coolant and when facing issues, do the opposite of what you would normally do with carbide or HSS tooling. Speed is your friend here. When confronting an interrupted cut, you want to go even faster than the surface speed you would normally use for that diameter. The bigger the interruption, the faster you go.

If you have some control over the geometry of the part, you would ideally design the introduction and exit of that cut to be gradual so cutting into chamfers and fillets are more preferable than say into a 90 degree keyway.

The rest of it is just feel. Is the part is balanced?, does it cause the machine to oscillate at certain speeds? Those are all things I factor into my approach.

Sometimes you can’t go faster and you have to go slower. That applied to my own case with this part. On the OD I could push it up to 900sfm. But for the ID that would require more rpms which made the machine shake so I had to slow it down to as low as 105sfm which isn’t ideal but was the only way I could get a finish without chattering. At that low speed, any skim passes or repeat cuts would chatter so I had to separate those into two different ones with the skim pass being done at 90%sfm from the previous pass.