LOL no probs Rich.
Sebastian
With the mention of your cut being 0.2 out I was just wondering if it was when you were doing code like you posted? If you were measuring the circle cut for both the big dia and then what was left, the core so to speak?
If thats what you are doing then the core will be big dia - cutter dia - 0.2mm as you have a 0.1mm finish on the big dia.
Hood