• Micrometers Inside micrometers are precision measuring instruments that use a calibrated screw to measure interior distances on a workpiece, such as the span between two edges, or the diameter of a circle or hole. Rotations of the micrometer’s screw amplify small distances that cannot otherwise be measured directly, translating those turns to a measurement that can then be read from a scale, dial, or electronic display.
  • Bore gauges Bore gauges are precision measuring instruments used to measure or transfer measurements of the interior diameter of holes, or bores, in a workpiece at any depth. Simple bore gauges are used with a caliper to transfer the hole measurement, while more complex gauges take the measurement directly and display it through a vernier, dial, or digital display.