Angularity

Controls a surface, line, or axis at a specified basic angle relative to a datum.

∠

0.20

Angularity controls orientation at any specified angle other than the special cases of 0 degrees and 90 degrees.

The angle itself is basic; the tolerance value is a linear distance between boundary planes, not a plus/minus angular tolerance.

Use angularity for bent tabs, ramps, tapered faces, stamped features, and mating surfaces that must sit at a functional angle.

It can control surface flatness and orientation in one requirement when the surface must mate cleanly at an angle.

Bent Flange Held At A Basic Angle

The basic angle defines the ideal orientation. The GD&T tolerance controls the envelope around the angled surface.

\u2220

0.20

Two parallel planes or a cylindrical zone oriented at the basic angle to the datum.

The part is usually constrained to the datum and tilted with a sine bar or fixture so the angled feature can be swept like a flatness check.

A CMM can evaluate the oriented tolerance zone directly from the datum reference frame and basic angle.

A stamped hook face has angularity 0.20 mm to datum A at a basic 30 degree angle. A scan shows 0.14 mm total spread normal to the ideal plane.

Ideal plane

30 degrees basic to A

The datum and basic angle establish the center of the tolerance zone.

Surface spread

0.14 mm

Variation is checked as distance between parallel boundary planes.

Compare

0.14 <= 0.20

The full surface fits in the angularity zone.

The hooked feature passes without tightening the entire thickness tolerance.

Control	Basic Angle	Datum	Best Use
Angularity	Any angle	Yes	Sloped or bent features
Perpendicularity	90 degrees	Yes	Square faces and axes
Parallelism	0/180 degrees	Yes	Constant spacing between faces

Perpendicularity is angularity at 90 degrees, and parallelism is angularity at 0 degrees.

Like other orientation controls, angularity requires a datum reference.