Geometric Dimensioning Reference Chart
- When applied to a feature-of-size
- Can also be used as a form control without a datum reference
- When a datum feature-of-size is referenced with the MMC modifier
- When an MMC modifier is used
- Automatic per rule #3
- The symmetry symbol’s characteristics were not included in the version of the chart that this chart is derived from. The symmetry symbol was dropped from the Y14.5M standard around 1988 and re-added around 1994. (It’s been speculated that it will be re-dropped the next time the standard is revised.)
|Least material condition (LMC)|
|Maximum material condition (MMC)|
|Projected tolerance zone|
|Regardless of feature size (RFS) (note 1)|
|Unilateral (note 2)|
- The symbol is not part of the 1994 version. See para. A5, bullet 3. Also para. D3. Also, Figure 3-8.
- The symbol is not part of the 1994 version. It is in “Y14.41-” and may appear in a future version of Y14.5. It refers to unequal profile distribution.
- All the symbols above are used in a feature control frame to specify a feature’s description, tolerance, modifier and datum references.