Engineering · GD&T
Angularity.
An orientation tolerance for surfaces and axes at any specified angle other than 0° or 90°. Tolerance zone is two parallel planes (or a cylinder) at the basic angle to a referenced datum.
01 · Definition
Same as parallelism, different angle.
Angularity completes the orientation triplet alongside parallelism (0°) and perpendicularity (90°). For any other angle, angularity is the right control.
The basic angle (the nominal target) is shown on the drawing as a basic dimension — typically boxed (e.g., 30° in a frame). The angularity tolerance specifies how much the actual feature can deviate from that basic angle, expressed as a tolerance zone bounded by two parallel planes (or a cylinder) at the basic angle to the datum.
02 · FCF and example
Angled mounting surface for sensor.
A defense electronics housing with a sensor-mount surface specified at 30° to the base (datum A). The drawing shows the basic angle in a frame (e.g., a boxed 30°) and the angularity FCF as ∠ 0.005 A. The actual surface must lie within two planes 0.005″ apart, both oriented exactly 30° from datum A.
Inspection: 5-axis CMM with the actual surface measured against the basic-angle plane. The high-low difference is the actual angularity error.
Production: 5-axis machining is the right tool. 3+2 indexed lets you mill the angled surface in one setup with full surface-finish control. See 5-axis vs. 3+2 and our 5-axis machining centers.
03 · Common applications
Where angularity matters.
- Aerospace bracket pad-up surfaces at non-square mounting angles
- Optical mounts for off-axis sensors and beam-splitters
- Defense fire-control housings where sensor packages mount at calculated angles
- Hydraulic manifolds with angled port intersections
- UAV pylons and missile-mount hardware with off-vertical attachment angles
Keep exploring
Related tools & references
Full feature-control-frame symbol reference.
The 90° special case of angularity.
The 0° special case of angularity.
See how angular orientation stacks across an assembly.
Choosing realistic angularity callouts.
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