What is bonus tolerance?

What is bonus tolerance?

• A. Additional tolerance gained when the actual size moves away from MMC toward its opposite material boundary.
• B. A reduction in tolerance when the feature is oversized.
• C. Tolerance applied to a projection zone.
• D. Tolerance that remains constant with size.

Answer: (A)

Bonus tolerance is the extra tolerance you get when a feature’s size moves away from its MMC (minimum material condition) toward the opposite material boundary. In GD&T, the tolerance zone for other features (like position or profile) can expand as the actual size departs from MMC, giving this additional “bonus” allowance. For a hole, the MMC is the smallest permissible diameter; if the hole ends up larger than MMC (moving toward the opposite boundary), the tolerance zone for related features can grow by the amount of that size deviation. In other words, the farther the size is from MMC toward the opposite boundary, the more tolerance is effectively available. This is why bonus tolerance is described as extra tolerance gained with size variation, not a fixed or reduced tolerance.

Bonus tolerance is the extra tolerance you get when a feature’s size moves away from its MMC (minimum material condition) toward the opposite material boundary. In GD&T, the tolerance zone for other features (like position or profile) can expand as the actual size departs from MMC, giving this additional “bonus” allowance.

For a hole, the MMC is the smallest permissible diameter; if the hole ends up larger than MMC (moving toward the opposite boundary), the tolerance zone for related features can grow by the amount of that size deviation. In other words, the farther the size is from MMC toward the opposite boundary, the more tolerance is effectively available. This is why bonus tolerance is described as extra tolerance gained with size variation, not a fixed or reduced tolerance.