True position calculator
GD&T true position from measured X and Y deviation, with bonus tolerance from the feature's actual size at MMC or LMC. Pass or fail against the drawing tolerance.
True position calculator
Turn the X and Y deviation off your CMM or height gauge into a position error, add bonus tolerance from the feature size at MMC or LMC, and see if the hole passes.
Center may be up to 0.0070 in from basic in any direction at this size.
Position tolerance is a cylindrical zone, so the error is the diameter of the circle through the measured center: error = 2 · √(ΔX² + ΔY²). Add ΔZ² for a projected or 3D zone.
At MMC, every bit the feature departs from its maximum material size is bonus: bonus = |actual − MMC size|. For a hole MMC is the smallest hole, for a pin the largest. LMC is the reverse.
allowed = drawing tolerance + bonus, pass if error ≤ allowed. A feature outside its size limits fails on size first and gets no bonus.
Per ASME Y14.5. Datum shift from a datum feature at MMC is not included here.
ΔX and ΔY are measured minus basic, in the datum reference frame on the drawing, not raw machine coordinates. If the datum features themselves are referenced at MMC, there may be additional datum shift the tool does not account for.
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