Pipe taps are used to create a threading system inside a hollow pipe. Such taps are generally the accepted tool for this purpose. There are few, if any, other tools designed to do that particular job.
In mechanical machining and pipe fitting applications, from time to time the end of a pipe needs to be threaded inside. This is done to create a receiving, or female, end of the pipe. When these situations arise, there is generally only one particular piece of machining equipment used to create the threads in any metallic pipe: a pipe tap, also referred to as a threading tap.
A pipe tap is generally made out of hardened steel or some form of steel alloy that makes it harder than most metals that common pipes are made out of. This is because as the pipe tap is inserted into the pipe end, it has to be turned and pressure must be applied to the tap or it won’t properly cut the pipe thread. The thread-cutting grooves on the tooled end of the pipe tap have channels or gaps in them that allow for the collection of the cut material, so the user is able to discard them as the thread is cut into the interior wall of the pipe.
The design of the other end of the pipe tap typically depends on the manufacturer. Some pipe taps are considered manual, which means they have a steel shaft that has one end for cutting and the other for a handle. This allows the thread to be cut by hand with the use of a hand saw.
Other, more recent models of the pipe taps have been given a machined end for tapping. The other end is shaped like that of lug or nut. This allows for the pipe tap to be fit into a tool of some sort, such as a powered device or a simple hand tool that may be used to turn the tap into the pipe.
The most important aspect of using the pipe tap is ensuring an even or “plumb” entrance to the pipe end. This is important because if the thread is cut into the pipe end in an uneven manner, when the male pipe end is turned into the thread it won’t allow for a straight connection. The two pipes would then be joined at an angle.