Tools Supplies

An Engineering Tap is a tool used for cutting threads inside a hole or bore. There are various types of taps each with their own particular application, some are used to start a thread and others are used to finish a thread, particularly when trying to achieve a full thread in a flat bottom hole. These taps are known as “plug” taps. On the form of a plug tap the threads at the bottom of the tap hardly taper at all, probably 1 to 1.5 of the threads are tapered from the bottom towards the top of the tap. These taps can be used to “bottom” the hole to create a full thread from top to bottom of the bore. They are normally used following the taper or second cut tap, being unable to start a thread on their own, because the flat bottom of the plug tap does not allow successful starting of a cut. In the U.K. these taps are known as plug taps, but in the U.S.A. they are called bottoming taps.