What is RFS (Regardless of Feature Size)?

• A. The tolerance is applied independent of the actual size of the feature.
• B. The tolerance is applied relative to the nominal size.
• C. The tolerance is applied with respect to a datum reference frame.
• D. The tolerance is modulated by material condition.

Answer: (A)

RFS means the specified tolerance does not change with the actual size of the feature. When a callout has no size modifier, the tolerance value is fixed and applied independent of whether the feature is larger or smaller than nominal. For example, a true-position tolerance of 0.5 is a constant allowance: the feature’s center must lie within a 0.5 diameter cylinder about the true position, regardless of the hole’s actual diameter. This is different from tolerances that are modulated by material condition (MMC/LMC) or by size; those would widen or tighten the tolerance as the feature size changes. The other options either imply dependency on nominal size, rely on datum relations in a way that isn’t what RFS defines, or describe modulation by material condition, which RFS explicitly does not do.