A PCD Runout Checking Gauge is a precision inspection tool used to measure the runout (wobble or eccentricity) of features located on a Pitch Circle Diameter (PCD)—such as holes, studs, or gear teeth—relative to a reference datum, usually the bore or center axis of a part. It’s essential in applications where equally spaced features must be precisely positioned around a circle, such as bolt patterns, gear teeth, or turbine blades.

To ensure that all features on the PCD are equally spaced and centered around the datum axis. To check for eccentricity caused by manufacturing errors or wear. To maintain proper balance, fit, and assembly performance.