How To Measure Thread Size Female. Using a ruler or vernier, measure across the outside diameter of a male or hose tailpiece thread or measure the inside diameter of a female thread. A thread’s pitch size is the number of threads per inch.
Use a thread pitch gauge to determine the number of threads per inch or the distance between threads in metric connections. Hold the pipe in 1 hand and take a ruler or tape measure in your other hand. (on metric threat types, it’s the distance between threads.)
(on metric threat types, it’s the distance between threads.)
Set a nickel on top of the aerator, and if it's almost the same circumference, the aerator is a regular size. Using the thread pitch gauge, align the gauge on the threads and make sure it is snug. Also known as nhr or mht. Place the gauge on the threads until the fit is snug.