Productivity and GD&T

Perpendicularity

Perpendicularity

The condition of a surface or axis at a right angle to a datum plane or axis.

Parallelism

Parallelism

The condition of a surface, line or axis which is equidistant at all points from a datum plane or axis.

Concentricity

Concentricity

That condition where the median points of all diametrically opposed elements of a figure of revolution.

Total Runout

Total Runout

A composite control of all surface elements.

Circularity

Circularity

A condition where all points of a surface of revolution, at any section perpendicular to a common axis, are equidistant.

Flatness

Flatness

All the points on a surface are in one plane, the tolerance specified by a zone formed by two parallel planes.