How to measure threads

By using a combination of three tools, identifying connectors is easy to do.

A caliper is used to measure the O.D. of a male thread and I.D. of a female thread.



NOTE: When comparing your measurements with those on our charts it should be remembered that threads can become worn and distorted from use and you may not compare exactly to the figures in the tables.

For your convenience, dimensions are in both millimeters and inches.



The thread pitch gauge measures the threads per inch. For metric threads the gauge will identify the distance between the threads.



The seat angle gauge is used by placing the gauge angle on the sealing surface. The centerline of the end fitting and the gauge should be parallel.

In the English system the thread size and pitch (number of threads per inch) are given, along with the thread type.