Check concentricity

Measuring runout and axial runout with a runout tester

Specific position tolerances are a tolerance group that includes directional tolerances as well as running and location tolerances. Position tolerances describe the maximum permissible deviations from a specific ideal position of two or more components or two or more planes relative to each other. In most cases, either one of the components or a specific plane is defined as a reference. This reference element or reference plane, from which the corresponding position tolerances originate, must be specified in the technical drawing.

The specific positional tolerances are subdivided as follows:

Positional tolerances: Running tolerances

The runout tolerances include the radial runout as well as the axial runout. Total runout and total axial runout, on the other hand, are grouped together under the term total runout tolerances. Here, the axis of a workpiece serves as a reference. In practice, the workpiece is rotated about this axis in order to measure this tolerance. With a Runout tester the radial and axial runout is measured.

Position tolerances: Location tolerances

These include: the position, concentricity, symmetry and coaxiality. The maximum permissible deviation of structural elements, such as slots or bores, from their nominal position is defined. By defining these position tolerances, the coaxiality of a bore or the symmetry of a slot, for example, is ensured in practice.

Position tolerances: Directional tolerances

The definition of suitable directional tolerances is of decisive importance, especially for mechanical engineering. For example, appropriate tolerancing of the angles between different assemblies, such as the machine table and boring mill spindle, guarantees the functionality of machines. The following direction tolerances exist: parallelism, perpendicularity and angularity