Hmm,
The posted code in your reply #26 shows a change in the X value for the last circle to be cut by 0.1mm and thus increases the diameter
of one circle from a diameter of 34.2mm to 34.6mm. Additionaly that shifts the concentricity of the two diameters such that at 12 & 6
o'clock difference between is 0.1997, at 3 o'clock 0.1, and at 9 o'clock 0.3.
Now with a 12.7mm dia cutter you figure what the finished cut diameters would be but they will not be 30.
maybe I am missing something
RICH