Also known as a micrometer screw gauge, micrometers are a type of precision measuring tool. Displaying metric and imperial measures, they’re used to accurately obtain micro measurements.
As the name suggests, micrometers are used to measure minuscule diameters of roughly less than 2.5cm.
What is a micrometer used for?
Micrometers were invented in the 17th century by the English astronomer, William Gascoigne. By inserting his astronomical micrometer into the eyepiece of a telescope, he was able to measure the size of celestial bodies in relation to one another.
In recent years, micrometers have been used in mechanical engineering and machining sectors where the accurate measurement of tiny components is essential.
Micrometer components
Micrometers have come a long way in the last few hundred years. Once cumbersome and difficult to operate, you’ll find micrometers from companies like RS are portable, easy-to-use, and highly accurate. Micrometers are comprised of only a few key components.
Frame – The c-shape frame helps provide the optimum position of the anvil and barrel.
Anvil – Attached to the one end of the c-shape, the anvil helps secure the item being measured. Investing in a model with a carbide-tipped micrometer helps extend the tool’s lifespan.
Sleeve or barrel – The linear scale is etched onto the sleeve or barrel and measurements are taken in degrees of .001 for truly accurate readings.
Locking nut – This helpful feature ensures the spindle is secured in place. For added accuracy, choose a model with a locking level instead of a lock nut, as they tend to be easier to use and maintain.
Spindle – The spindle is fixed to the opposite end of the frame to the anvil.
Thimble – The thimble can be rotated with light pressure and helps provide a clear reading of the measurements.
Ratchet stop – When measuring tiny components you need precision and the ratchet stop helps limit and enable movement at a calibrated torque.
How to use a micrometer?
When using a micrometer you should hold it in your dominant hand, whilst you hold the object in your non-dominant hand. With the hand that is holding the micrometer, you can hold the thimble between your thumb and index finger and slowly begin turning until the object is securely held between the anvil and the spindle.
You can then take your reading.
How do you read a micrometer?
The reading of a micrometer is equal to the reading of the main scale plus the reading of the thimble scale. The UK’s mechanical engineering industry is worth over 49 billion euros, so ensuring the accuracy of even the smallest parts is essential. To maintain accurate readings, it may be necessary to recalibrate the micrometer every so often.
This is relatively easy to do, but care should be taken to ensure you don’t damage any vital components. You should find a small hole located in the sleeve that will fit a spanner’s pin. This can be depressed to start the recalibration process.
