An indicating micrometer is a precision measuring instrument that combines the high-resolution features of a micrometer with a mechanical dial or digital indicator to show small displacements more clearly and accurately. Instead of relying solely on the thimble and sleeve graduations like a traditional micrometer, an indicating micrometer uses an internal lever mechanism that transfers the motion of the spindle to a dial or digital readout.
This setup makes it easier to detect minute variations in size—often in the range of 0.0001 inches or 0.001 mm—and is especially useful for comparative measurements, such as checking part dimensions against a known standard or master. Unlike a traditional micrometer that’s best for direct measurements, an indicating micrometer excels in comparative precision—identifying how much a part deviates from a nominal dimension.