How to use micrometer

1. Place the object whose length, diameter, or thickness is to be measured between the micrometer's measuring rods.

2. Turn the barrel or friction screw to close the rods around the object to be measured. The rods should lightly touch the object between them but not clamp down on it.

3. Flip the locking lever to lock the measuring rods in place.

4. Read the value just exposed by the thimble on the central line of the cylinder. This value is in millimeters. Typically, there is a mark every half-millimeter, with the millimeter marks rising above the central line and the half-millimeter marks going below it.

5. Read the mark on the thimble aligned with the central line on the cylinder. This mark is in hundredths of millimeters. There are 50 such marks, meaning that each turn of the thimble corresponds to half a millimeter, the distance between the upward and downward marks on the cylinder central line.

6. Step 6

   Add these values together. This is the measurement of the object between the measuring rods.