Category: Location

True Position – Position Tolerance

by GD&T Basics on December 22, 2014.

Controls exactly where a feature must be located. Uses a circular tolerance zone and works with MMC — the most used symbol in GD&T.

Concentricity

by GD&T Basics on December 15, 2014.

Controls whether the median points of a cylindrical feature share the same axis as a datum. Expensive to inspect — position or runout usually works better.

Symmetry

by Tom Geiss on November 4, 2014.

Controls whether the median points of a feature are symmetric about a datum plane. Like concentricity, it's rarely the right call — position is usually preferred.