A long nut is another term for a coupling nut or a connecting nut. A connecting nut, or more commonly referred to as a coupling nut, is used to join two bolts, male threaded rods, or pipes together. It may also be used to extend length. It can join any two externally threaded objects as long as both are of the same diameter and thread pitch. For example, it can couple a hanger bolt and a threaded rod or two threaded rods.

At times, a coupling nut may also be used as a standoff or spacer to raise one part of an assembly higher than the other. If connecting two external items with different sizes, you should get the reducing connecting nut. There are instances as well when you need to tighten a rod assembly inware or to press it outward. Coupling nuts can also help you with either of those applications.

It is slightly different from a sleeve nut in that a coupling nut offers a right hand thread. Whereas, a sleeve nut offers both left and right hand threads plus it’s usually longer. The taper also begins in the middle to the end, with a stop in the middle.