Total Runout

Controls

Total indicator movement swept across the entire surface — not just one slice — as the part rotates and the indicator traverses along the datum axis. For cylindrical surfaces it controls circularity + straightness + taper + eccentricity simultaneously. For flat faces it controls flatness + perpendicularity.

A part that passes circular runout at every slice could still fail total runout if the individual readings do not land in the same total band.

Example

A precision grinding spindle nose must satisfy total runout 0.005mm across its full cylindrical journal length. A single-slice runout check is insufficient because the grinding wheel follows the spindle path — any taper or bow compounds the size error. Total runout ensures the entire journal sweeps within one tight envelope.

Inspection

• Bench centres or V-blocks + dial gauge traversed slowly along the full surface during continuous rotation
• The indicator must not be re-zeroed between positions — the single TIM reading spans the whole surface
• CMM full cylinder scan with simultaneous axial and radial data
• More demanding to set up than circular runout — spindle speed and traverse rate must be controlled

For face total runout: traverse the indicator radially across the face while rotating — the zone is two parallel planes perpendicular to the datum axis.

Datum & Modifiers

Total runout is a stricter requirement than circular runout — where both are possible, start with circular runout unless the full-length envelope matters functionally.