I finally figured out why my finish passes kept chattering, and it was my own dumb fault
I was running a batch of 40 aluminum brackets last Tuesday on the Haas and every single one had chatter marks on the finish pass. I kept blaming the tool holder and swapped it out three times, then checked my feeds and speeds like five times. Finally my lead guy came over, watched me for maybe 30 seconds, and said my setup block was sitting about .015 out of flat on the vise jaw. I had been tightening the back jaw bolt first instead of working front to back, so the whole part was rocking just enough to mess with the cut. Been doing it that way for almost two years and never put it together. Ran the next set his way and got a mirror finish with the same tool I thought was junk. Anybody else have a setup habit they picked up early that turned out to be wrong the whole time?