Basics and Use Tips for Micrometers in Metal Measurements

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Basics and Use Tips for Micrometers in Metal Measurements

There are a few elements that may be part of many projects involving metal and steel products, and measuring is one of these in many cases. You need to be able to measure dimensions with full accuracy for any kind of project here, and one of the tools that’s often most useful for those in this position is the micrometer.

At Wasatch Steel, we’re happy to provide clients with a wide range of steel products and steel services, ensuring they’re fully prepared for any metal project they have a need for. What is a micrometer, and how can it be properly used for any kinds of measurements or dimensional needs within your metal project? Here’s a basic primer.

What is a Micrometer?

For those just learning about it for the first time, a micrometer is a type of measuring device that’s used for both flat surfaces and certain other geometric shapes. It’s made up of a sleeve, a thimble, a Vernier scale and two surfaces, which are known as the anvil and spindle. They measure dimensions by using the principle of a screw, which is why micrometers are also known as screw gauges.

Micrometers are meant to measure finite distances, and are broken down into various sizes based on the specific measuring needs of the user. The smallest micrometers have a measurement range of just 0-25mm, while the largest have a range of 0-300mm.

They’re mainly used in engineering and manufacturing, but anyone with a need to get accurate measurements of small objects or tight spaces can find them useful.

Types of Micrometers

Generally speaking, there are three types of micrometer used today:

  • Inside micrometers: This micrometer will be used to measure inner dimensions of products, such as the inside diameters of pipes, tubes and similar objects.
  • Outside micrometers: As the name suggests, outside micrometers are meant for measuring outer dimensions on products. This would include the outside diameters of objects like washers, dowel pins and more.
  • Depth micrometers: These aren’t as common as the others, but they’re ideal for measuring various depth dimensions. This would include the depth of slots, blind holes and other similar objects.

Simple Use Tips for Micrometers

How do you go about using a micrometer? This will vary slightly between the types of micrometer you’re using, which we discussed above, so our basic steps below will be specific to outside micrometers (likely the most common type used today).

Here’s how to go about using the micrometer:

  • Ensure secure item: First and foremost, the object being measured must be securely clamped in place. This could mean using a vise, being extra careful or even enlisting the help of another person to hold it down while you take the measurement.
  • Loosen the thimble: Once you’re confident your part is secure, you can loosen the thimble by turning it counterclockwise. You don’t need to remove it entirely, but you should turn it until there’s a small amount of play in the spindle. This allows for the anvil to be placed on the outside of the surface of the part that’s being measured.
  • Turning thimble: From here, it’s time to begin turning the thimble clockwise, which will start moving the spindle toward the part that’s being measured. As you do this, the spindle and anvil should get closer and closer together. There is no need to apply excess force here — in fact, doing so may damage the accuracy of the measurement. For this reason, many micrometers will come with a ratchet on the thimble to prevent too much pressure.
  • Reading: Finally, when the anvil and spindle have been placed in contact with the part simultaneously, you can start reading the measurement. There are two ways to do this, depending on what type of micrometer you’re using. We’ll go over these in our next section.

Reading the Micrometer Scale

Here are the options available for how to read a micrometer scale:

  • Traditional scale system: The much older and more well-known version here is the traditional scale system, which comes with either two or three different specific scales that are used together to display measurements. These scales are known as the sleeve scale, the barrel scale and the Vernier scale (this scale may not be present on all micrometers, but it adds precision for those it’s included on). Each of these three scales will be observed and used to write down the correct measurement.
  • Digital scale system: The digital micrometer, on the other hand, will simply display a measurement that can be read directly from the electronic screen. You don’t need to worry about any of the different scales here — just look at the number displayed and you’ll have your measurement.

If you have the funds available, digital scale systems are generally highly preferred today. They involve much less operator error and are simply more accurate overall. However, if you’re working with a limited budget, the traditional scale system can still get the job done (albeit with a bit more care and effort).

There’s no doubt that micrometers are excellent tools that can be used in a variety of different situations where precision measurements are required. They allow for much greater accuracy than ruler alone, and they’re not terribly difficult to use once you understand the basics. Use the tips above next time you need to take measurements with a micrometer and you’ll be sure to get great results.

For more on this, or to learn about any of our steel or metal services, speak to the team at Wasatch Steel today.