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What is the anvil on a micrometer?

Today we are going to outline micrometer anvils with a specific focus on flat and spherical micrometer anvils. As a basic and changeable component of the micrometer, understanding shapes and corresponding uses of the anvil is important. The micrometer anvil is the part of the micrometer that remains stationary while the measured object is held against it. The anvil connects directly to the frame of the micrometer and varies in shape depending on the measurement task. In fact, micrometers are classified into types depending on the shape of the anvil on the tool. Some micrometers are even designed to have an interchangeable anvil that can be exchanged based on need. We are focusing on two of the most common shapes for a micrometer anvil—spherical anvils and flat anvils. Each design comes with its own advantages and common uses. We are going to help you better understand the purpose behind the micrometer anvil and under what circumstances in which each one is preferred.

What material is a micrometer anvil made from?

The most commonly used material for modern micrometer anvils is carbide material. Older micrometer anvils often were made entirely of steel, but this material did not hold up as well after extended use and most manufacturers have switched to carbide. A layer of carbide is located on the anvil face and helps to harden the surface resulting in higher accuracy and increased durability. Carbide is often also layered on the spindle of the micrometer. The carbide material used is typically made up of carbide and some other element with lower electronegative property. When comparing it to steel, carbide material has a number of advantages for use on a micrometer anvil. Carbide hardness and density are twice that of steel, its melting point is more than 1000°, and it has a thermal expansion much lower. All of these factors help to make a more durable and reliable tool.

What are the most common types of micrometer anvil?

Flat micrometer anvil

The flat micrometer anvil is the most commonly used type of micrometer anvil. Recommended for most uses, the flat micrometer anvil is a sensible purchase given how many different measurement tasks it can be used to complete. When using a flat anvil micrometer, you can gather measurement information quickly and directly, with very high resolution. The readings collected from these tools are fast, simple, and accurate. The flat anvil surface on a micrometer is recommended to be used particularly when measuring thickness and diameter.

Spherical micrometer anvil

The spherical micrometer anvil is sometimes known as a ball micrometer anvil. The anvil on a spherical anvil micrometer is shaped in a curved formation, like a ball. Due to this ball shape, the anvil touches the object being measured only at one specific point, as opposed to across the whole surface of the anvil. This feature makes spherical anvil micrometers ideal for measuring thickness on rounded surfaces such as tubes. While tube micrometers can also accomplish this feat, spherical anvil micrometers can be used to measure other rounded surfaces apart from tubes. Ball micrometers or micrometers with a spherical anvil are often used for reloading purposes as well.

How do you know which type of anvil to use?

Comparing flat anvil micrometers to spherical anvil micrometers

The main purpose of having and using a spherical anvil, or ball anvil, is to measure the thickness of a wall on a tube or other cylindrical objects. Additionally, spherical anvil micrometers are ideal for measurements requiring a single tangential point of contact on both sides, for example when collecting data on the pitch diameter of a screw thread. Importantly, when using a spherical anvil, the ball diameter must be taken into account when determining the final micrometer reading. While some micrometer builds may automatically account for this, needing to make this subtraction may be viewed as a disadvantage of this tool over flat anvils which do not require such an adjustment. The flat anvil micrometer is the most recommended for a reason. This flat-shaped anvil can be used to take measurements across any object that is not curved in some way. With incredible versatility, the flat micrometer anvil can be broadly applied, giving you more bang for your buck. You will want to regularly check the flatness of the anvil to ensure accurate and precise measurement.

Selecting the correct anvil on your micrometer

The type of anvil you need will vary depending on the measurement application. The flat micrometer anvil is the most commonly purchased and most commonly applied anvil shape. However, other micrometer anvil shapes exist for good reason. A special type of anvil may be required for completing tasks like measuring wall thickness on a tube or measuring a delicate object like paper. If you are working with a curved surface, such as on a tube, you will want to be using a spherical micrometer anvil. If you are working with a flat surface, such as to get the thickness of a material, you will want to be using a flat micrometer anvil. Knowing what measurement task you will be completing is at the heart of knowing whether to use a flat micrometer anvil or a spherical micrometer anvil.


When comparing flat anvil micrometers to spherical micrometers, the bottom line is that they are best suited for different measurement needs. If you are concerned about deciding between these two anvil shapes, you might consider getting a universal micrometer or a micrometer set with interchangeable anvils. This sets you up for tackling any measurement job you may have. However, if you are certain of the types of measurements you are going to be completing with your micrometer, then deciding on either a flat anvil or a spherical anvil should be done based on intended use. Contact us at Higher Precision today for more answers to your specific questions about micrometer anvils.


Why is carbide the most commonly used material to make micrometer anvils?

Micrometer anvils today are covered in a layer of carbide material. For a long time, micrometer anvils were made out of steel and you can still find a number of steel micrometer anvils today. However, steel is not as durable a material as carbide and so many of the anvils made today are covered in a layer of this more enduring substance. Carbide material consists of carbide mixed with another material with a lower electronegative property. As compared to steel, carbide material comes with important advantages for lasting accuracy when using your micrometer anvil. First, the melting point of carbide is more than 1000°, second, carbide has a significantly lower thermal expansion point than steel, and third, carbide has a density and a hardness level twice that of steel. These qualities increase the durability and reliability of the micrometer anvil, making it the most commonly used material today.

What are the common types of micrometers available based on anvil shape?

The most common types of micrometer anvils today include flat micrometer anvils, spherical micrometer anvils, v-shaped micrometer anvils, blade micrometer anvils, and tube micrometer anvils. The anvil shape required depends entirely on the type of measurement job at hand. The flat micrometer anvil is the most common anvil shape available. The flat micrometer anvil is used for measuring flat surfaces and thicknesses, providing fast and accurate data. The spherical micrometer anvil is also known as a ball micrometer anvil. The spherical micrometer anvil is best used when measuring curved surfaces and uses a single point of contact with the object. The v-shaped micrometer anvil looks just like the letter “v” and holds an object in place using these secured two points of contact. V-shaped micrometer anvils are ideal for measuring balls. The blade micrometer anvil looks very similar to a flat head screwdriver and is thin and slender in shape. The blade micrometer anvil is used to take groove diameter measurements. Finally, the tube micrometer anvil is shaped like a tube and vertically positions, making this anvil ideal or taking measurements of tubes and other bores.

How do you choose whether to use a flat micrometer anvil or a spherical micrometer anvil?

The choice between a flat micrometer anvil and a spherical micrometer anvil really comes down to a matter of measurement type. Spherical anvils are used to collect measurements when working with a curved or cylindrical surface. When a single tangential point of contact is needed for a measurement, then a spherical anvil is also ideal. One disadvantage of using a spherical anvil is needing to account for the diameter of the ball in your final measurement. Flat micrometer anvils, alternately, are used to measure when a flat surface is involved. These are the most commonly purchased and owned types of anvils because of their broad application. Importantly, flat anvils require regular flatness checks to maintain accuracy. If you are intending to be working with rounded surfaces like balls or wall thickness on a tube, then a spherical micrometer anvil is likely best. However, if you are typically going to be measuring flat surfaces and structures, then a flat micrometer anvil is what you will need.


Flat micrometer anvil

A flat micrometer anvil is a specific shape of anvil used in conjunction with a micrometer. The anvil on a micrometer sits opposite the spindle and is used to hold the object being measured in place. The flat micrometer anvil is perfectly flat all across its surface such that it lies directly on the object. Flat micrometer anvils are the most commonly used anvil shape and are applied when taking measurements of flat surface.

Spherical micrometer anvil

A spherical micrometer anvil is a specific shape of anvil used in conjunction with a micrometer. Sitting opposite the spindle, the anvil of a micrometer holds the measured object in place. The spherical micrometer anvil, also known as a ball micrometer anvil, makes contact with the object at one point, making these anvils perfect for measuring thickness on cylindrical or rounded surfaces.

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