The measuring head has a scale etched on it, which is divided into equal parts of 0.01 mm or 0.001 inch. When the spindle moves in or out of the measuring head, the scale moves relative to a fixed index line, which allows the user to read the measurement accurately.

In addition to the scale and index line, Mechanical Digit Counter Micrometers also have a digit counter mechanism that records the number of full rotations of the thimble. The digit counter mechanism consists of a series of gears and numbers arranged in a window on the micrometer body. The digit counter is typically used to add the number of full rotations to the reading obtained from the scale and index line, which provides a highly precise measurement.

To use a Mechanical Digit Counter Micrometers , the user places the object being measured between the spindle and anvil and applies pressure until the spindle contacts the object. The user then rotates the thimble until the object is firmly held between the spindle and anvil. The user then reads the measurement from the scale and index line and adds the number of full rotations indicated by the digit counter mechanism.

Overall, Mechanical Digit Counter Micrometers are highly precise and accurate measuring instruments that are widely used in manufacturing and engineering applications where precise dimensional measurements are essential.