What is circularity?

What is circularity?

• A. A form tolerance controlling the roundness of a circular feature.
• B. A size tolerance for hole diameter.
• C. A positional tolerance for circular feature locations.
• D. A runout tolerance for circular edges.

Answer: (B)

Circularity is a form tolerance that specifies how round a circular feature must be. It limits how far the actual contour can deviate from a perfect circle, measured in any plane perpendicular to the feature’s axis. The tolerance zone is a circle with the specified diameter, and all points on the surface must lie within that circle across all cross-sections. This cares about roundness rather than size, location, or runout, so it is distinct from a size tolerance for diameter, a positional tolerance, or a runout tolerance.

Circularity is a form tolerance that specifies how round a circular feature must be. It limits how far the actual contour can deviate from a perfect circle, measured in any plane perpendicular to the feature’s axis. The tolerance zone is a circle with the specified diameter, and all points on the surface must lie within that circle across all cross-sections. This cares about roundness rather than size, location, or runout, so it is distinct from a size tolerance for diameter, a positional tolerance, or a runout tolerance.