Advanced Coordinate Technology
STRAIGHTNESS

Straightness is the condition where all the points on a surface or an axis are in a straight line. A straightness tolerance specifies a zone within which the surface or axis must lie. In the example the zone is bounded by two parallel lines 0.03mm apart.

When a diameter symbol is added to the tolerance the derived axis of the feature must lie within a cylindrical tolerance zone of 0.03mm diameter.

When a MMC modifier is added, the tolerance zone is 0.03 diameter at 18mm diameter and the zone increases as the feature decreases from MMC. 		Straightness example