The measurement of the different distances is done through very specific instruments. These vary depending on the length that you want to measure, or in the medium that the measurement will be made. And, when it comes to very small, extremely small distances, the micrometer is the instrument to turn to.


What is a micrometer?

When we talk about a micrometer, we are talking about an instrument for measuring small lengths . It is a tool for measuring sizes in tiny proportions. It is usually calculated in millimeters, and its uses vary from measuring objects or very small distances.

  • Micrometer Features
  • History
  • What is a micrometer for?
  • Types of micrometer
  • Parties
  • How does it work
  • How to use
  • How to read a micrometer
  • Importance

Micrometer Features

The measure has been, almost always, an important object of concern on the part of the constructor or constructor of works. Over the centuries, humans came up with their own measurements to roughly calculate the dimensions of something. It is known that, in fact, an English king took his arm as the measure of all things!


Measuring long and medium distances is not that difficult. It is, after all, something that can be taken into account through the steps we take with our feet. Not for nothing, one could see a gentleman measuring the great distances of a jousting road with his own steps.

But, nevertheless, the situation is complicated when we talk about slightly smaller distances. Small distances can be measured, in this case, by taking references of equal sizes. But what if the distance is smaller than the tiniest? What if the measurement is less than what the eye can quantify? The micrometer comes to make up for this lack.

Developed a long time ago in order to meet the need to measure distances between the stars, this instrument is a tool that measures quite small dimensions. In fact, the common thing is that its maximum measurement point is 50 mm. This, as you can see, is a very small dimension.

From the etymology, micrometer is the result of a conjugation. It comes from the Greek “micro” and “metron” , which mean “small” and “measure” . It is, therefore, the measure of everything small. This instrument is based on the use of a screw that gradually approaches the other end. From its proximity or remoteness, the meter can estimate the dimensions of the instrument in question.


As already stated, its origins lie in the astronomer’s need to measure the distances between the stars. Historically, the first antecedent of this is found in Galileo Galilei , who had the urgent need to calculate the distance between the moons of Jupiter . After this first attempt, other inventors tried to continue this tradition, such as those of William Gascoigne . Other names like Henry Maudslay and Jean Paul Laurentthey perfected this instrument, always in the vein of those inherited by the industrial revolution. However, it would not be until the final days of the 19th century that an American inventor and businessman would patent the instrument and take it to its ultimate consequences.

What is a micrometer for?

Its usefulness or purpose is in the measurement. It is known that there are some objects whose dimensions are so small that measuring them with conventional instruments becomes an impossibility in many cases. It is to this population of objects that the micrometer directs its energies. Its usefulness is precisely in the measurement of quite small dimensions (around the millimeter).

Types of micrometer

One can come across various types of micrometer on the market. We could say that its variety arises from the need to monopolize the demand that this instrument presents in it. Depending on the type of measurement to be taken, we can divide the micrometer into the following types:

  • Exterior Micrometer : Its name is due to the fact that it measures the exterior dimensions of an object, just as the name implies. It is the most frequently used type of micrometer.
  • Inside Micrometer : It is distinguished from the previous one by its measurement object. Measure, this time, the inside of an object.
  • Depth Micrometer : In this case, we find an instrument that calculates the size of the depth of a groove. An example of this can be seen in the holes made by perforations in a construction.


Let’s see, now, some of the most important parts of this instrument . To do this, we will take into account the Exterior Micrometer, a prototypical model par excellence.

  • Body : This is the large body of the instrument. It usually comes with a special insulation made to prevent changes in measurements due to dilation effects.
  • Stop : It is the end that puts a limit to the advance of the screw. It is the point from which the micrometer cannot measure anymore.
  • Screw : Mobile element of the instrument. It is the one that allows making the measurements of the object.
  • Fixing Lever: Another element that slows down the movement of the screw, preventing variations in measurements.

How does it work

Depending on the design , these may vary slightly in performance . However, the essential elements remain unchanged. A threaded screw is being turned by a mechanism with which it is associated. This mechanism will bring the screw closer to the stop, or as far as the object under study allows. The reading of the measure will depend on the mechanisms in use.

How to use

Its use is actually quite simple. An object is placed in support on the top of the instrument. Then, while we hold the object, the other hand will turn the screw as far as the object allows. Your measure will be read below.

How to read a micrometer

To know how to read the micrometer , we have to take into account whether its measurement is made in inches or millimeters.

Here is a bit of information about it:

  • Inches : The maximum value that can be reached is 1 inch, and its measurement is made per thousandth of an inch. Each complete turn is equal to a quarter inch, or 25 thousandths of an inch. The only way that can be followed is to calculate the number of turns made with the screw (each proportion appears on the handle) and add them with the hundredths that appear as the screw turns in one direction or another.
  • Millimeters : In this case, a full rotation refers us to half a millimeter. In this case, the amounts expressed in the handle (each one equivalent between 0.1 and 0.50 millimeters) will be added with the numbers that appear as the thread is turned. In this case, the 5 millimeters plus the 0.30 millimeters of the handle could be added. In total, resulting in about 5.30 millimeters.


It is important that we emphasize its importance, since it is one of the most used instruments in metal mechanics and other professions where the measurement of a small object is necessary. Such things are, as already stated, difficult to estimate with conventional instruments, this having one of the highest levels of precision in the industry.

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