A simple proportional measuring gauge consisting of two straight brass or steel arms, pivot-jointed at one end to form an adjustable gap gauge which is set to the required size (or gap) by a slotted quadrant plate secured to one arm at the opposite end from the joint, and locked with a screw. The two arms and quadrant plate are marked with numbered scales and are used primarily to ascertain the correct proportions between a clock wheel and the pinion to be geared with it. As a wheel and pinion gauge it is limited in its accuracy above and below certain dimensions, for it cannot take into account the various forms of pinion-leaf addenda curves. The gauge, however, is invaluable to the clockmaker for obtaining other measurements.