What is the effect of a projected tolerance zone on mating part clearance at projection height?

• A. It guarantees zero clearance at all heights.
• B. It ensures the projected portion will have tolerance relative to the mating part at the projection height.
• C. It negates the position tolerance.
• D. It applies only to non-projected features.

Answer: (B)

The main idea is that a projected tolerance zone extends a feature’s tolerance zone upward to a specified projection height so the fit with a mating part is controlled at that height. By projecting the tolerance zone, the tolerance for the feature’s true position is maintained not just at the actual feature surface but at the height where the mating part will contact or interface with it. This ensures the mating part will have the intended clearance or interference at the projection height, which is critical for assemblies where the feature extends into or through another part.

This does not guarantee zero clearance at all heights—clearance depends on the actual sizes involved. It also doesn’t cancel the position tolerance or apply only to non-projected features; it specifically governs how the feature must sit relative to its mating part at the defined projection height.