Choosing the Right Dial Indicator

December 7, 2018 8:48 am

Indicators are instruments utilized in various contexts to measure small distances and angles and amplify them to make them obvious.

Machinists use this precision measuring tool in a great number of applications, ranging from determining the accuracy of a lathe or mill alignment to setting parts accurately on a faceplate.

As any person who worked in a machine shop will know, indicators exist in two different formats: Dial Indicators (DI) and Dial Test Indicators (DTI).

What’s the difference between them?

The explanation is very simple: dial test indicators have lever-type contacts, while dial indicators have plunger-type contacts. 

Test indicators are also smaller and lighter than dial indicators.

Both types of dial indicators are handy and relatively easy to use, and, although there are several overlapping applications, they are often employed for separate tasks.

Dial indicators are best for comparative and repetitive measurements while test indicators are used most often to explore relatively broad part surfaces in either one or two dimensions – for example, measuring variations in height, flatness, or roundness.

Although dial test indicators are generally used more often in job shops, we generally recommend having both.

Which one is the best?

This guide by Long Island offers a complete analysis and comparison of all the test indicators on the market.






Don’t have time or don’t want to spend money on a reference guide? No problem. We did some research, collected members opinions and put together a list for you.


Dial indicators


Mitutoyo Dial indicator

As often happens when we recommend products, Mitutoyo makes its way to the top of the list.

Although not inexpensive, this dial indicator is reliable, long lasting and precise.




Starrett Dial Indicator

Starrett is another authority when it comes to precision measurements tools. Mechanically solid, durable and made in America.





Teclock Dial indicator

One of the most recommended from Practical Machinist members.






Dial Test Indicators


Brown & Sharpe dial test indicator

THE dial test indicator. Often considered the gold standard for test indicators, the Interapid has a very low measuring force and it’s smooth as glass. Well worth the investment.





Mahr Federal Dial Test Indicator

Slightly cheaper than the Interapid. Mahr Federal is a staple when it comes to metrology.





Digital indicators


Mitutoyo Digital Dial Indicator

Dial Indicators are available with Digital Readouts too, although most machinists prefer the analog dial. If you are a digital tools advocate, Mitutoyo has what you are looking for.





Dial Indicator Stand


Regardless of the type of tool you are going to use, it’s always convenient to have a stand to secure the dial indicator and facilitate the measurement process.

Here’s what we and Abom79 recommend




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  • David Birch says:

    Of minor concern when setting up a test indicator is the orientation of the contact arm to the work movement, and is specific to manufacturer and even model. Some provide optimum accuracy when positioned at 90 degrees to the work; some specify that they are calibrated at a 15 degree angle. The difference in reading is usually insignificant, but is measurable (“sine error”).

  • its actually a cosine error and only applies to test indicators that have the lever arm for measurement.the 15deg is the angle between the lever arm and the surface being measured. if the angle is greater than 15 degs, the length of the lever arm is foreshortened to the point that it affects the measurement. compute the cosine of 15 deg=.966, its pretty close to 1. that value times the length of the lever arm is the foreshortened length which is less than the the calibrated lever arm length.

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