dial indicator

The small indicator 0-9 tells you how many times the large indicator went around. one full circle on the large indicator is .100 inches. each little hash is .001 inch. So for example if the small indicator is between 4 and 5 and the large dial is on 50 which is .050" that would be a total of .450 inches.

The gauges should turn so that once you set up the dial indicator and place the pin against one of the teeth, you can "zero" the reading and take a proper measurement.