Thanks for reading.
I have a 2010 Mag-Fadal 4020 CNC Mill. We are trying to face a 4" x 4" piece of 3/8" thick 304 stainless plate flat on both sides with the minimum amount of material removal possible. I am using a basically brand new Shars (I know, I know) 3" APKT style face mill with brand new inserts. No matter what direction I run the cutter, no matter what speeds and feeds, I ALWAYS get a ~.001" step where the toolpaths cross. I have run the cutter in the X direction, climb and conventional, in the Y direction climb and conventional, I have used zig-zag patterns, circular/spiral patterns and nothing will get rid of it. I went so far as to completely re-tram the mill to within .0006" over 18". I have double checked and changed the inserts for edge quality and checked the torque on the body holding screw. Everything is tight. The only thing I can think of that could allow that much flex is the drawbar, but that was rebuilt no more than 4 months ago and had ~1400# holding pressure. Am I missing something obvious that is preventing me from running what seems like a very simple operation? I'll try anything at this point...