AFAIK Just the position. That is the toroid I milled with the smaller endmill. It was a profiling toolpath. The original David calibration PDF files had that circle a just twice the diameter of the black dot. The white center was the same diameter as the other black dots. the new calibration panels seem to have bigger donuts, but I have only seen pictures, and I don't know why they may have done that. Perhaps it helps David with the calibration?
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