Best 7 Types of Micrometer

The micrometer is an essential and liner measuring tool. It is more accurate than the vernier. It is a c-shape frame. It is also called a caliper due to its similar appearance to the caliper. It is used in the mechanical sector for exact measurement.

Before discussing all  first know what is the micrometer?

Also ReadBest 7 Types of Vernier Caliper

What is Micrometer?

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It is also known as micrometer screw gauges. It is an essential measuring tool. It is used by mechanical engineers, machines, and workers in other technical trades. By using this equipment they get extremely fine measurements. It is displayed in imperial and metric format.

It is a linear measuring instrument. It can measure the thickness, diameter, and lengths of solid bodies.  It is created of a C-shaped frame. The frame with a movable jaw regulated by an integral screw. Another name of the micrometer is caliper. It was named due to its similar appearance to the caliper.

It is capable of a greater degree of measuring accuracy than other tools. The other equipment such as the dial caliper and vernier caliper.

Types of Micrometer:

There are several types are available. In the mechanical sector outside types are most used. Inside and depth micrometers are more appropriate for use in certain strategies. There are some types given below.

Ball Micrometers:

It contains a spherical anvil. It is used to measure the thickness of the wall, the distance between the hole and edges. It is opposed to the tube type.

Digital Micrometers:


Sometimes in a normal equipment, we found incorrect reading. To avoid this problem we use a digital type. This digital type gives the measurement in digital format.

External Micrometer:

It is primarily used to measure the external dimension. The external dimension is like the dimension of shaft and thickness. Its accuracy is 0.01mm.

Tube Micrometers:

It is designed to measure tube thickness. Its main feature is cylindrical anvils. The anvils are found perpendicular to the spindle. It is eligible for quick and perfect measurements than the other tool.

Screw thread Micrometer:

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It is mostly used to measure the pitch diameter of screw threads. Here nut and screw mechanism work. Its accuracy is 0.01mm and 0.001mm. It consists of the same parts as an outside micrometer. The movable spindle is pointed in this type.

Two-pin inside Micrometer:

It is used to measure the initial dimension like diameter, slot, etc. Here nut and screw mechanism work. Its two-pin is made from tungsten carbide. Other parts are made from invar steel.

Three-pin inside Micrometer:

It is used for measuring internal diameter. Here nut and screw and rapper screw mechanism works. It’s a pin made from tungsten carbide material. Its other parts are made from invar steel.

Parts of Micrometer:

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It is designed as reshaping. It assures the outstanding positioning of the anvil and barrel. We can take a variety of shapes and sizes. It allows for the intended function. For taking ideal and highly accurate measurements the hub-shaped frame is used.


The anvil should be shiny. It should assure that the spindle gravitas is the object. It is firmly secure. The anvil will be protected in consistent contact with the part. For quality models, carbide-tipped anvils are used. It allows high tool life.

Sleeve or Barrel:

The sleeve and barrel is kept securely in his place. It is common for vernier makings to be found on this part. This scale is highly accurate for measurements.

Locking Nut:

When we take reading some time it disturbs. To avoid this thing we set the locking nut. Some micrometers come perfect with locknuts. Some others we use locking levers. So choose a variety of locking levers for easy use and maintenance.


The spindle is a shiny cylindrical component. It affects the thimble to move toward the anvil.


You apply pressure to the thumb to turn the thimble. The thimble is used for easy reading.

Ratchet Stop:

The ratchet stop is fitted in the end part of the handle.

Why we use Micrometer?

It is manufactured for a special reason. By using this equipment we measure a very small object. It allows a very precise measurement of any object. It firs between the anvil and spindle. The external micrometer can be used to measure length, depth, and thickness.

Principle of Micrometer:

It transform a small distance into large rotations of the screw. It can be read easily from a scale.

The basic principle are given below:

  • The rotation quantity of a screw can be directly and correlated. A screw lead moves forward axially with a 360° turn.
  • The lead and diameter of the screw will be amplified in circumferential movement.

Reading procedure of a Micrometer:

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The micrometers are a suitable tool for measuring cylindrical and spherical-shaped objects. There is some procedure to read easily.

  • At first, know the basic knowledge about the equipment.
  • Before using it clean it by using a soft cloth. It is necessary to remove any kind of debris that is placed between the anvil and spindle.
  • Start the positioning of the object being measured. Notice that the object is stable and avoids any scratching. You control it for freehand.
  • Then roll the ratcheting anti-clockwise and the 0 points on the thimble.
  • It is set according to the sleeve scale. Roll the spindle until the spindle is within close contact with the object.
  • When it is near the contact of the object the thimble lock should be applied.
  • The spindle is possible to adjust as required. When you know it completes its function you can remove the object.
  • At the removing time of the object take care of the anvil and spindle surface to scratching.
  • Then we get the reading. At reading time conform that spindle is kept stable.

Precautions for Micrometer:

  • Before using it should be properly cleaned with a soft cloth.
  • Before use, it should be confirmed that it is faultless.
  • It is not used on machines in operation and on a rough surface.
  • Before using job should be properly cleaned.
  • For setting micrometer ratchet stop used.
  • After measuring it should be locked and then a reading should be taken.
  • When we keep it anvil and spindle should be divided.
  • It should be saved from the water.
  • It should be kept separate from other ordinary tools.
  • We should never put heavy oil in it.

Micrometer Accuracy:

Its accuracy may be evaluated about two key factors. The first one is the accuracy of the screw thread. The second key factor is any process errors. The accuracy is 0.01mm.

Difference Between a Micrometer and a Caliper:


  • It is used to establish the size of a different object.
  • It is used for measuring exterior or inside dimensions.
  • the accuracy is being ±0.00005.


  • It is also used to establish the size of a different object.
  • Calipers are used to establish physical dimensions, interior measurements, exterior measurements, and depths.
  • The accuracy of calipers is commonly between ±0.001


Here I explain micrometer definition, types, parts name, reading procedure, and precautions. These are the basic thing to know for a mechanical employee. If anyone knows these things he /she measure perfectly of a small object.

Thank you

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