OK, once again my poor choice of words has derailed my point. You can substitute "vibration" for instances of "chatter" in my description of the pullout problem areas, because that is more what I was attempting to imply than conditions specific to the traditional machinist's definition of tool chatter. Of course we should not be operating under chatter conditions under normal circumstances. Chatter is a specific condition that is a problem by definition, yet it correlates with cutter-induced machine vibration and TTS pullout conditions, but it's not the whole story about TTS pullout by any means. Steve, if you aren't cutting steel, I'm not surprised that you aren't getting chatter. I'm interested in cutting mild steel, and while I have had plenty of successes, along with them I've had plenty of struggles to avoid chatter and pullout for some operations, such as profiling with a reasonable DOC and shallow WOC. This is where machine design and setup differences are most pertinent, when intermittent high loading forces are imposed in repetitive and complex radial and axial loading directions. First vibration starts at light loading, then you get chatter at higher loads, and maybe you get TTS pullout somewhere in there too, or maybe you don't.