Micrometer is a gauge which measures small distances or thicknesses between its two faces, one of which can be moved away from or towards the other by turning a screw with a fine thread. The metric micrometer looks very similar to a standard inch micrometer until you look at the graduations on the sleeve and the barrel.
Reading the Metric Micrometer To read the metric micrometer, first read the number of whole millimeters on the bottom row of the sleeve of the micrometer . These are the whole millimeters. If there is an additional line uncovered on the top row, this is equal to one-half a millimeter . So 0.5 mm would need to be added to the measurement. Then add the thimble reading to whole and half millimeter sleeve readings.