GD&T Concepts

Feature

Axis

Feature-of-Size (FOS)

Maximum Material Condition (MMC)

Bonus Tolerance

Tolerance Stack

Datum

Full Indicator Movement

Datum Target

Control

Median Points

When using GD&T tolerances, there are additional concepts that are required to clarify the use of GD&T symbols. These pages explain some of the major items required to read and interpret GD&T callouts.