How to Read a Thread Gauge

Updated July 20, 2017

A thread pitch gauge or a thread gauge is also known as pitch gauge. It is used to measure the pitch of a screw thread or a tapped hole. The pitch is the distance between adjacent threads. Thread gauges come in different sizes to enable measurements of very small to very large threads. A thread gauge has a number of blades that can be used to measure pitch of different sizes. Each blade has a marking that determines the pitch it corresponds to.

Familiarise yourself with the markings on the blades of the pitch gauge and make a note of whether the units mentioned are in inches or in millimetres. The number of the blade determines the distance between two adjacent teeth or pitch of the thread.

Take the first blade of the pitch gauge and hold its toothed edge against the threads of the bolt. Observe if the teeth exactly match the threads. If not, move on to the next blade and repeat the process. Continue testing the blades until you find the perfect match.

Read the marking on the blade of the thread gauge that matched perfectly with the bolt threads. This is the pitch of your bolt.


If you are performing these measurements in a workshop, make sure that you take all necessary precautions, such as wearing safety glasses, hats, gloves, and boots. Failing to do that may results in injury from heavy articles and machinery in the vicinity.

Things You'll Need

  • Bolt
  • Thread gauge
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About the Author

Naeem Ahmed has been an established author of technical literature since 1989. He has numerous publications to his credit in peer-reviewed research journals such as "Physical Review Letters" and "Nuclear Instruments and Methods in Physics Research." With a Ph.D. in physics from Siegen University in Germany, he is an active researcher and academic.