When applying a pattern position tolerance, what should be referenced?

When applying a pattern position tolerance, what should be referenced?

• A. Only the outer silhouette of the pattern.
• B. The pattern position tolerance referencing the DRF and datums as needed.
• C. A depth-based tolerance unrelated to datum references.
• D. A surface finish specification.

Answer: (B)

Pattern position is defined relative to a coordinate system established by datums—the datum reference frame. When you apply a pattern position tolerance, you specify how the centers of the pattern features must lie within the tolerance zone with respect to that DRF, using whichever datums are needed to constrain location and orientation. The DRF provides the true position reference so the pattern will align consistently with mating parts. The other options don’t fit because the outer silhouette doesn’t define the centers, depth-based tolerances aren’t about location, and a surface finish spec isn’t related to the positional tolerance.

Pattern position is defined relative to a coordinate system established by datums—the datum reference frame. When you apply a pattern position tolerance, you specify how the centers of the pattern features must lie within the tolerance zone with respect to that DRF, using whichever datums are needed to constrain location and orientation. The DRF provides the true position reference so the pattern will align consistently with mating parts. The other options don’t fit because the outer silhouette doesn’t define the centers, depth-based tolerances aren’t about location, and a surface finish spec isn’t related to the positional tolerance.