What Is a Thread Coupler?

A thread coupler is a simple mechanical device used to join threaded pipes or solid bars together. The coupler consists of a short length of metal or plastic sleeve cut on its inner or outer surface with a screw thread. This thread corresponds to threads cut on the ends of the items requiring joining. To make the joint, the threaded bars are simply screwed into or onto either end of the thread coupler until a tight joint is achieved. This type of coupler is extensively used to join threaded bars, pipes, and concrete-reinforcing rods.

Couplers are essential components in any industry or application where runs of hose, piping, or bar stock require joining. These couplers are available in an astounding selection of types, sizes, and materials, and in an equally-extensive spread of sophistication and functionality. The simplest of these, however, are the members of the thread coupler family of joint devices. These humble couplers consist of a simple sleeve cut on their inside or outside surface with a standard screw thread designed to screw onto or into a corresponding thread on the joined components.

To use the thread coupler, the ends of the pipe or rod need to be threaded with an external or internal thread of the same pitch as that of the coupler. The end of one of the pipes is screwed into the coupler until its edge is approximately halfway down its length. The process is then repeated with the other length of pipe. This brings the two edges of the pipes up against one another inside the coupler sleeve. Thread coupler types with external threads will usually be equipped with a raised collar or flange in their center against which the pipes are screwed tight with a pipe wrench.

In general, these couplers are made of the same material as the pipes or rods that they are designed to join. In some cases, couplers made of plastic may be fitted with a threaded metal sleeve to strengthen the coupler. The outer surface of the thread coupler may be of a plain profile or include a hexagonal section or raised projections to allow for tightening with a wrench or purpose-designed tool. There are also internal threaded couplers that screw into threads cut on the insides of pipes. Common uses for the thread coupler include the joining of concrete reinforcing rods, irrigation and potable water supply pipes, and threaded bars.