Measurements provided by a micrometer are made up of a combination of values taken from the sleeve scale, the thimble scale and, on some micrometers, the vernier scale.
Micrometer sleeve scale
The sleeve scale of a metric micrometer has a measuring range of 25mm.
It is graduated in millimetres and half millimetres.
The scale is numbered every 5mm.
Micrometer thimble scale
The thimble scale has a measuring range of 0.5mm (the smallest value that can be measured on the sleeve scale).
It is divided into 50 increments, with each increment representing 0.01mm (0.5 ÷ 50 = 0.01).
The scale is numbered every 0.05mm.
Micrometer vernier scale
Some also have a vernier scale on the sleeve, which provides the user with readings of even greater accuracy (to 0.001mm).
The vernier scale has a range of 0.01mm and is graduated in 10 increments, each of which represents 0.001mm.