Location Tolerance (Location Deviation)
Location tolerance determines the location (true position) of the feature in relation to a reference. A datum is always necessary to indicate location tolerance; as such, it is a geometric tolerance for features related to datums.
True position
The true position requirement specifies the accuracy of the position in relation to the datum (reference plane or line).
- a
- Within 0.1 mm dia.
- Explanation of drawings
- The centre of the circle indicated by the indication arrow must be within a circle with a diameter of 0.1 mm.
Coaxiality
The coaxiality requirement specifies the coaxiality of the axes of two cylinders (no deviation of the central axis).
- Explanation of drawings
- The axis of the cylinder indicated by the indication arrow must be within a cylinder with datum axis line A as the axis and a diameter of 0.03 mm.
Concentricity
The concentricity requirement specifies the accuracy of concentricity of the axes of two cylinders (no deviation of the centre). Unlike coaxiality, the datum is the centre point (plane).
- a
- Within a circle with 0.05 mm dia.
- Explanation of drawings
- The axis of the cylinder indicated by the indication arrow must be within a cylinder with datum axis line A as the axis and a diameter of 0.05 mm.
Symmetry
The symmetry requirement specifies the accuracy of how symmetrical a target is to the datum (reference plane).
- a
- Within 0.05 mm from the theoretical centre plane
- b
- Theoretical centre plane
- Explanation of drawings
- The centre plane indicated by the indication arrow must be between two parallel planes symmetrical to the datum centre plane A and separated from each other by 0.05 mm.
