Just bringing this to a close, there were actually 2 things going on here… First off, we found some chatter on the Z axis that was causing vibrations during the cut, 1F support took care of that immediately (great job guys!).
Second “issue” is that I’m machining a 3D object full of ARCs and the 1F does not do ARCs. I was not aware of this so I assumed it was a mechanical issue. Luckily it seems like it’s just a matter of finding the right settings… More on this here: Lets talk about ARCs and Circles