Geo Tolerance Symbols
Geo tolerance symbols usually means GD&T geometric characteristic symbols: straightness, flatness, position, profile, runout and the other controls used in feature control frames.
geo tolerance symbols geometric tolerance symbols gdt symbols gd&t symbols chart
What the symbol controls
The symbol names the geometric characteristic. The tolerance value defines the allowed zone size, and datums locate or orient that zone when the control needs references.
GD&T families
- Form: straightness, flatness, circularity and cylindricity.
- Profile and orientation: profile, angularity, perpendicularity and parallelism.
- Location and runout: position, concentricity, symmetry, circular runout and total runout.
When to calculate
Use the symbols chart to read the callout, then use true position, MMC bonus, flatness or runout calculators when inspection data needs a numeric pass/fail check.
Frequently asked questions
Are geo tolerance symbols the same as GD&T symbols?
In most search and shop usage, yes. GD&T is the formal drawing language for geometric dimensioning and tolerancing.
Does every GD&T symbol need a datum?
No. Form controls do not use datums. Orientation, location and runout controls usually do.
Related pages
- GD&T symbols chart - 14 geometric characteristics, datum use and tolerance-zone meanings.
- How to read GD&T symbols - feature-control-frame reading order and examples.
- True position calculator - position error from measured X/Y deviation.
- MMC bonus tolerance calculator - bonus tolerance from feature-size departure at MMC.
- Flatness tolerance calculator - surface form check from measured point data.