Micrometer Screw Gauge

Label of the Parts

(This image is licienced under GDFL. The source file can be obtained from wikipedia.org)

Range and Accuracy

  1. The range of a micrometer is 0-25mm.
  2. The accuracy of a micrometer is up to 0.01mm.

How to Use a Micrometer?

  1. Turn the thimble until the object is gripped gently between the anvil and spindle. 
  2. Turn the ratchet knob until a "click" sound is heard. This is to prevent exerting too much pressure on the object measured. 
  3. Take the reading.
Youtube Video

How to Read the Reading?

Reading = Reading of main scale + Reading of thimble scale.

Reading of main scale = 0 - 25 mm
Reading of thimble scale = 0 - 0.49mm


(This image is licensed under GDFL. The source file can be obtained from wikipedia.org.)

Reading of main scale = 5.5mm
Reading of thimble scale = 0.28mm

Actual Reading = 5.5mm + 0.28mm = 5.78mm
Youtube Video

Precaution Steps

  1. The spindle and anvil are cleaned with a tissue or cloth, so that any dirt present will not be measured. 
  2. The thimble must be tightened until the first click is heard. 
  3. The zero error is recorded.

Interactive Animation
SHAW : micrometer (Java Applet)

External Link
The Micrometer - Upscale.Utoronto.ca