Similar to other geometric tolerance group, run-out can be split into two categories, a 2D (circular run-out) and 3D (total run-out) variant.

Circular run-out can control the circularity of a feature relative to the components axis bounded by a 2D tolerance zone. This can be considered as measuring a combination of the component’s co-axiality and roundness at multiple cross sections along the applied length as the part rotates.

When Circular Run-out is measured, the probe remains static whilst the component is rotated, creating an individual ‘circular’ measurements. This is then repeated down the length of the part.

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Controlling other Features with Run-Out

Both circular and total run-out can also be applied to a perpendicular surfaces relative to a datum axis.

Circular run-out applied to a perpendicular surface will only consider the surface perpendicularity as, like its measure of circular features, measurements are taken at multiple circular positions. The 2D tolerance zone created will be applied parallel to the datum axis direction.