The application discloses embodiments of a lapping head including a sensor device in the base structure of the rotating lapping head. For operation, rotation is imparted to the lapping head through a drive motor coupled to the lapping head through a rotating shaft. As disclosed, the sensor device is electrically connected to one or more electronic components or circuitry through the rotating shaft and a rotating electrical connector coupled to the rotating shaft. In embodiments disclosed, the sensor device is an eddy current sensor configured to measure a gap dimension between a sensor element on the lapping head and a conductive platen to provide an in-situs measurement of workpiece thickness.