I'd use cooling fluid for lubrication for starters. Another tip is to (and here's where's not being a native speaker is a disadvantage so I'll try to describe) leave enough material on for the last cut. What you could do in cases like this is cut until your radius is some 1 mm off, and then take the last milimeter of in one pass instead of almost getting there and then taking another 1/10th of. I hope it helps. Oh and take your speed down. It's not like you have a factory.