In technical drawing, we might see labels as shown in the attached figure. The circled M and L are meant for Maximum Material Condition (MMC) and Least Material Condition (LMC). Anyone has any idea what does the 'S' stand for? Thanks.
I'll try to dig up a copy of ANSI Y14.5, but in the mean time, I found a table that says "S" means RFS (Regardless of Feature Size), which is the default when no other modifying symbol is specified. A few types of tolerances can only apply in an RFS context.
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Ok, I found ASME Y14.5M-1994, but it doesn't show that circled-S symbol. It says the symbol for RFS is "none". Maybe an older or newer version of Y14.5 defines S.