Definition

A notched SCALE placed at right angles to the movable wire of a MICROMETER and so designed that one turn of the MICROME­TER SCREW will move the micrometer wire across one notch of the comb; the central notch of the comb in conjunction with the zero of the microme­ter head furnishes a fiducial point from which all micrometer readings are reckoned. The comb is used for keeping count of whole turns of the MICRO­METER SCREW, parts of turns being read on the gradua­ted micrometer head.