Would it be okay to put a ultegra 6600 branded seat post in a cnc lathe to take off .005-.01 inches, facing the material and getting rid of these nasty scratches? I was not intending to face the first 10cm that is inserted the frame, so clamping will not be a problem. I'm just wondering if taking .02 inches off the outer diameter over a 10-15cm span of the post will cause failure.
In my opinion it won't cause any issues...but I don't know bike structural tolerances.
Also I might note that while cnc lathing a seat post might seem far out there, I happen to be training on cnc machines and a little practice on my own stuff gives me something to do before I risk screwing up clients' stock.