How To Use Digital Calipers

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Digital calipers are quite simple to use but require a certain amount of skill and practice to use properly.

The first procedure is to make sure the caliper blade faces are clean and free of debris.

It is common practice to wipe the jaws clean with your fingers and check that the readout is zero with the jaws closed.

Using your digital calipers to achieve the most accurate measurement, you need to make sure you have them parallel and perpendicular to the faces being measured.

You need to check if this is true when looking from above and to the side.

The following diagrams explain the basics of using digital calipers.

demonstrating the correct way to use digital calipers
demonstrating the wrong way to use digital calipers
demonstrating the wrong way to use digital calipers
using digital calipers to measure the inside of a pipe

Measuring a Depth

Typically the hardest measurement to achieve accurately is using the depth blade on the rear of the calipers.

Holding them perpendicular to the measured face can be quite tricky and multiple measurements may be needed to get a consistent reading. 

using digital calipers to measure a depth

It is not uncommon for two different machinists to get quite different measurements of the same depth.

What are Digital Calipers used for?

Measuring two external or internal faces and depths from one parallel face to another, also internal and external diameters. 

To put it more simply, they can be used to measure almost everything you need, and do it quite accurately.

Sure there are other measuring instruments that will do specific jobs more accurately and consistently but digital calipers can be considered a ‘jack of all trades’ when it comes to measuring.

Are Digital Calipers ideal for the hobby machinist?

This question is a no brainer. They are essential for anyone with any type of cnc machine. If you don’t already have a set you need to buy some now!

See my ‘best Digital Calipers‘ article to see what buying options you have.

They are more versatile for a hobby machinist than using micrometers.

How long will Digital Calipers last? 

If you don’t abuse them, a good quality set of calipers will last many years. I own a set of Mitutoyo calipers that I have had and used consistently for 15 years. 

They are getting worn out now and in need of replacing but they still work just fine. (Both of the jaws are wearing slightly at the tips through use.)

Cheap vs Quality Calipers

The one measuring tool any machinist should not cheap out on….

Digital calipers are a tool you will rely on and use the most, you want them to be as accurate and consistent for as long as possible.

Mitutoyo calipers
Mitutoyo Calipers, considered one of the best you can buy.

That does not mean you should not buy a budget set, they have many uses and having a set you are not worried about abusing or lending to someone can be useful.

But they will not be able to compete with the durability and accuracy of a quality set of digital calipers.

Digital Caliper Components

The anatomy of digital calipers

Are Digital Calipers necessary if I only use a cnc wood router?

Yes, you will still need a set. Even if you are only milling 3D reliefs and decorative projects you will still need them for measuring tooling, fixturing etc. 

How to Maintain Digital Calipers

Keep them clean – occasionally wipe them with a clean dry rag. 

Don’t drop them, if you do, check the tips of the jaws with a loupe (eye glass). If the jaws get damaged, use a flat stone to carefully smooth away any dings or burrs.

If your calipers aren’t coolant proof, don’t worry if they get splashed. All that happens is the readout goes doolally.

Wipe them dry and leave for a while and when all the moisture is gone they will work just fine. 

Are Digital Calipers Delicate?

If they fall off the bench into a bucket of oil, they’re screwed. 

If you throw them against a wall in a temper ‘cos you’ve just scrapped a job, they’re also screwed.

Solar Powered Digital Calipers

Don’t be tempted, they can keep switching off if you are trying to measure in a low lit area, which is extremely annoying.

The battery in a regular set will last a long time.

Digital Caliper Tolerance

A typical set of digital calipers will measure in increments of .0005” or .01mm on its readout. This is as high a tolerance as you can expect to get when measuring with calipers due to their design. Getting a repeat measurement with a smaller tolerance would be very unlikely.

Do You Need Digital Calipers?

Digital Calipers use a linear encoder to give the measurement on a digital display. Being digital enables manufacturers to add other useful functions. Primarily these are the ability to switch the readout between different measuring units and an incremental function.

If you are considering purchasing a set of digital calipers and would like my recommendation, the Mitutoyo 6″ digital calipers are in my opinion perfect for any machinist, not just a hobbyist.

Mitutoyo 500-196-30 Advanced Onsite Sensor (AOS) Absolute...*
  • Measures 0 to 6" (0 to 150mm) in 0.0005" (0.01mm) increments for precision use
  • Digital readout LCD shows inch or metric units for versatility when measuring
  • Advanced onsite sensor (AOS) electromagnetic inductive sensor for resistance to dirt, oil, and water
  • Measures inside, outside, depth, and step values for versatility. With thumb roller. Except 500-500-10, 500-501-10,500-502-10
  • Includes protective case and SR44 silver oxide battery
calipers in box
My new Mitutoyo Calipers!
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