Type of control | Geometric characteristics | Symbol | Character (Unicode) | Can be applied to a surface? | Can be applied to a feature of size? | Can affect virtual condition? | Datum reference used? | Can usemodifier? | Can usemodifier? | Can be affected by a bonus tolerance? | Can be affected by a shift tolerance? |
---|---|---|---|---|---|---|---|---|---|---|---|
Form | Straightness | U+23E4 | Yes | Yes | Yes (note 1) | No | Yes (note 1) | No (note 5) | Yes (note 4) | No | |
Form | Flatness | U+23E5 | Yes | No | No | No | No | No (note 5) | No | No | |
Form | Circularity | U+25CB | Yes | No | No | No | No | No (note 5) | No | No | |
Form | Cylindricity | U+232D | Yes | No | No | No | No | No (note 5) | No | No | |
Profile | Profile of a line | U+2312 | Yes | No | No | Yes (note 2) | No | No (note 5) | No | Yes (note 3) | |
Profile | Profile of a surface | U+2313 | Yes | No | No | Yes (note 2) | No | No (note 5) | No | Yes (note 3) | |
Orientation | Perpendicularity | U+27C2 | Yes | Yes | Yes (note 1) | Yes | Yes (note 1) | No (note 5) | Yes (note 4) | Yes (note 3) | |
Orientation | Angularity | U+2220 | Yes | Yes | Yes (note 1) | Yes | Yes (note 1) | No (note 5) | Yes (note 4) | Yes (note 3) | |
Orientation | Parallelism | U+2225 | Yes | Yes | Yes (note 1) | Yes | Yes (note 1) | No (note 5) | Yes (note 4) | Yes (note 3) | |
Location | Symmetry | U+232F | No (note 6 & 7) | Yes (note 6 & 7) | Yes (note 6 & 7) | Yes (note 6) | No (note 6 & 7) | No (note 6 & 7) | No (note 6 & 7) | No (note 6 & 7) | |
Location | Position | U+2316 | No | Yes | Yes | Yes | Yes | Yes | Yes (note 4) | Yes (note 3) | |
Location | Concentricity | U+25CE | No (note 7) | Yes (note 7) | Yes (note 7) | Yes (note 7) | No (note 7) | No (note 5 & 7) | No (note 7) | No (note 7) | |
Run-out | Circular run-out | U+2197 | Yes | Yes | Yes (note 1) | Yes | No | No (note 5) | No | No | |
Run-out | Total run-out | U+2330 | Yes | Yes | Yes (note 1) | Yes | No | No (note 5) | No | No |
Symbol | Character (Unicode) | Modifier | Notes |
---|---|---|---|
U+24BB | Free state | Applies only when part is otherwise restrained | |
U+24C1 | Least material condition (LMC) | Useful to maintain minimum wall thickness | |
U+24C2 | Maximum material condition (MMC) | Provides bonus tolerance only for a feature of size | |
U+24C5 | Projected tolerance zone | Useful on threaded holes for long studs | |
U+24C8 | Regardless of feature size (RFS) | Not part of the 1994 version. See para. A5, bullet 3. Also para. D3. Also, Figure 3-8. | |
U+24C9 | Tangent plane | Useful for interfaces where form is not required | |
Continuous Feature | Identifies a group of features that should be treated geometrically as a single feature | ||
Statistical Tolerance | Appears in the 1994 version of the standard, assumes appropriate statistical process control. | ||
U+24CA | Unequal Bilateral | Added in the 2009 version of the standard, and refers to unequal profile distribution. Number after this symbol indicates tolerance in the 'plus material' direction. |
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