MAAG Model TMA Gear Tooth Pitch Measuring Instrument, for checking the circular, normal or base circle pitch of spur gear teeth 0.85 to 12 DP. The difference in pitch between adjacent teeth, measured in ten thousandths of an inch, is obtained directly from the readings given by this instrument. With a dial indicator graduated in inches, it is equipped with the original wood case with wedges as seen in photos, built 1966
