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What does it mean when a feature control frame has no material condition modifier?

Last updated 10 August 2026

Regardless of feature size. RFS is the default in Y14.5-2018, so an empty modifier position is a statement rather than an omission.

There is no RFS symbol in the current standard and there has not been one since 1994. A frame with nothing after the tolerance means the tolerance applies at every size within the feature's size limits, with no bonus.

That matters commercially, because a modifier is where bonus tolerance comes from. A position at MMC on a hole gains tolerance as the hole grows away from maximum material condition; the same position with no modifier gains nothing. Reading an empty compartment as an oversight and assuming bonus is how a part gets accepted that should not have been.

Worked

The frame	⌖\|⌀0.01\|A
Control	Position
Family	Location control
Datum reference	required
Diametral zone	allowed
Material condition modifier	allowed
Legal under ASME Y14.5-2018	yes

Nothing in this frame contradicts Y14.5-2018. That is not the same as it being the right control for the job, the right datums, or a tolerance the process can hold.

Open this case in the calculator, and change the numbers.

Computed by ctrlPlanner. ASME Y14.5-2018.