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Tag: orientation

Parallelism

by Jason Richter on October 15, 2026.

Controls a surface or axis so it runs exactly parallel to a datum. Zero degrees is implied — no basic angle needed.

Perpendicularity

by Jason Richter on September 17, 2026.

Controls a surface or axis at exactly 90° to a datum. Squareness has a formal definition in GD&T, and this is it.

Cylindricity

by Jason Richter on July 24, 2026.

Controls the entire cylindrical surface at once — roundness, straightness, and taper combined. Stricter than circularity, and harder to inspect.

Reverse Inspections of Orientation

by Crystal Bemis on August 22, 2024.

In this Question Line video, Jason answers a question about reverse inspection of orientation and walks through an example to explain why you should not deviate from the inspection criteria given in the feature control frame.

Angularity

by Tom Geiss on November 7, 2014.

Controls a surface or axis at an exact angle relative to a datum. Requires a basic angle dimension — it's the orientation call for everything that isn't 0° or 90°.