How this calculator works
Coordinate offsets define a radial distance from the basic location. Doubling that distance gives the diameter of the centred tolerance zone needed to contain the feature centre. MMC or LMC adds departure from the specified material boundary. Size limits remain independent requirements.
Formula
position = 2 sqrt[(Xactual-Xbasic)^2 + (Yactual-Ybasic)^2]; allowed = drawing tolerance + bonus. Hole MMC bonus = actual-minimum; shaft MMC bonus = maximum-actual; LMC uses the opposite boundary.
Worked example
Offsets of 0.03 mm and 0.04 mm give a 0.10 mm diametrical error. A hole from 10.00 to 10.20 mm measured at 10.10 mm adds 0.10 mm MMC bonus to the stated position tolerance.
Advertisement
Frequently asked questions
Why multiply the coordinate error by two?
The radial centre offset must be expressed as the diameter of the tolerance zone.
Can bonus tolerance excuse an oversized hole?
No. A feature outside its size limits is rejected before position bonus is calculated.
Does this implement the whole GD&T standard?
No. Complex datum modifiers, projected zones, composite position and orientation along the full axis need a complete inspection method.