Find the work coordinate offset to add when touching off an edge with a probe or edge finder, since the readout is at the probe surface, not its center.
Offset = probe diameter / 2. Add this offset in the direction away from the part when touching the positive side, and subtract it when touching the negative side, so the recorded position lands at the true edge instead of the probe surface.
How it works
An edge finder or tool used as a probe contacts the part at its outer surface, but the machine records the spindle centerline position. The true edge is one probe radius away from that recorded position, in the direction the probe was pushed back from.
FAQ
Which direction do I apply the offset? If you touched off the positive side of a feature, subtract the offset from that reading to get the true edge. If you touched off the negative side, add it. Always sanity check by jogging to the calculated edge and confirming visually.
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