A compact reading index
The table below uses control names and tasks. For exact standardized glyphs, open the source illustration; similar-looking font characters must not be substituted on a manufacturing drawing.
Edition matters
Concentricity and symmetry were removed from ASME Y14.5-2018, as described by Mitutoyo’s change guide. They can still appear on older drawings or in different systems; do not automatically replace those requirements with runout.
Profile does not always need a datum
Form controls do not require a datum reference; profile can be specified with or without datum relationships depending on the full requirement. The old blanket statement that every non-form control needs a datum is incorrect.
Swipe to read all columns →
| Control group | Read this requirement | Next step |
|---|---|---|
| Form: straightness, flatness, circularity, cylindricity | Geometry of the controlled feature without a datum reference. | Read the complete requirement → |
| Profile of a line / surface | May be used with or without datum relationships; read the full callout. | Understand the reference → |
| Orientation: parallelism, perpendicularity, angularity | The specified orientation relative to the applicable datum relationship. | Establish the datum → |
| Position | The specified location zone, with its size, modifiers and applicable references. | Separate target and zone → |
| Circular / total runout | Rotation about the datum axis; single circular section versus designated surface extent. | Compare runout controls → |
Continue your task
Sources and review scope
Reviewed 23 October 2026. Arithmetic examples are labelled separately from source-table facts and standard scope.
ASME Y14.5-2018 (R2024)
Public standard catalogue and scope. Full clauses are not reproduced or independently audited here.
Open the original source ↗ISO 1101:2017
Public scope for geometrical-specification symbols and interpretation. Do not substitute it for ASME drawing rules.
Open the original source ↗KEYENCE — GD&T drawings and symbols
Manufacturer teaching: control groups, profile with/without datum relationships and theoretically exact dimensions. Not an exhaustive ASME 2018 symbol table.
Open the original source ↗Mitutoyo — Changes in ASME Y14.5-2018
PDF pp. 4, 12–16: removal of concentricity/symmetry from ASME 2018 and comparison with earlier editions. Manufacturer teaching, not the standard text.
Open the original source ↗