'using a fly cutter'- I'm wondering if it's possible for you to set an angle on the cutting edge such that it shears rather than chisels the material away. If you touch the cutting edge down to the workpiece, then look from that point of contact towards the axis of the flycutter, does the leading edge of the cutter parallel that view? What I'm suggesting is that looking along the leading edge of the cutter your view should take a line behind the rotational axis of the flycutter (spindle axis). I hope this is understood, and I don't know if there's a way you can adjust for this short of grinding this shearing angle into the cutting bit. Note this is not relief angles I'm talking about. I'll post a pic of what I'm suggesting if it comes to that.
I seldom do anything within the scope of logical reason and calculated cost/benefit, etc- I'm following my passion-