What Thread Is A Garden Hose?

Thread Types

A garden hose is typically threaded at either end with two distinct types of threading: National Pipe Thread (NPT) or National Standard Free-Fitting Straight Mechanical Pipe Thread (NPSM). NPT threads are designed to create a tight seal when used with a corresponding, threaded male fitting. NPSM threads are designed to be used in a slip-fit manner by relying on a gasket or other device to create the seal.

Thread Sizes

When discussing thread sizes, we're generally speaking about two metrics: thread pitch and thread diameter. Thread pitch is the number of threads per inch, whereas the thread diameter is the measure of the outside diameter of the threads themselves. Both NPT and NPSM thread sizes are expressed in imperial units, such as 1/2 inch 14 NPT or 1/2 inch - 14 NPSM. This indicates that the thread pitch is 14 thread per inch (TPI) with an outside diameter of 1/2 inch.

Tools for Thread Measurement

Thread measurement tools are an invaluable asset for those looking to accurately measure or verify thread sizes of a garden hose or any other device with threaded connections. Most common thread measuring tools are known as thread pitch gauges and consist of individual blades with the various thread accords etched into each. By selecting the blade with the closest matching thread, one can accurately check both thread pitch and thread diameter very quickly and without costing too much.

Reference Guides

Furthermore, there are many publications and reference books available for those who wish to further their understanding of various thread types and its usage. The ASME Handbook offers comprehensive information on threading, whereas Threaddata provides information specific to common thread types.

Insights

Garden hose threading can be daunting for the novice DIYer, but understanding the basics will make the job easier. Knowing the thread types and sizes are the most important pieces of information, as well as having the necessary tools to accurately measure them. With this information in hand, one can confidently select the proper fitting for the job.