Turns out I was clamping thin wall parts way too hard for like 2 years
I was running a batch of 6061 tube adapters last Tuesday and kept getting chatter no matter what I did with speeds and feeds. My lead guy walked over, loosened my vise about a quarter turn, and the finish came out mirror smooth on the next part. I had been cranking everything down like it was steel plate, and nobody ever told me thin wall stuff wants to float a little. How do you all judge clamping pressure on tube and thin plate without a torque wrench on the vise handle?