Reading a Metric Micrometer
Metric micrometers are similar to a standard micrometer. There are markings on the sleeve and on the thimble. You will notice the sleeve of a metric micrometer has markings on the top and the bottom. There's a handle lock and a ratcheting end to insure that the same pressure is applied for all readings.
Whole number increments are on one side of the sleeve and half millimeter increments are on the other. Depending on the manufacturer, these .50 millimeter or half millimeter increments may be on the top or the bottom. The micrometer in the illustration has them on the bottom. The thimble of the micrometer is separated into increments of .01 millimeters. Note that there are 50 divisions of .01mm on the thimble of a metric micrometer.
The micrometer on the top is set to 6.50 mm. There are 6 whole millimeters on the top and a half a millimeter on the bottom. The thimble is set to 0. When the three are added together the sum is 6.50 mm. It's important to remember that there are increments on both sides. A complete turn of the thimble will result in .50 mm or a half of a millimeter.
The micrometer on the bottom is 6.55mm. First add the whole number which is 6 millimeters. Then add in the .50 millimeter on the other side of the sleeve. Finally add in the .05 millimeters on the thimble totaling 6.55 millimeters.