Taps and dies are tools used to create screw threads, which is called threading. A tap is used to cut or form the female portion of the mating pair (for example a nut). A die is used to cut or form the male portion of the mating pair (for example a bolt). A taper tap has a more pronounced taper to the cutting edges. This feature gives the taper tap a very gradual cutting action. A taper tap is most often used when the material is difficult to work with, or the tap is of a very small diameter and prone to breakage. An intermediate tap is the most commonly used tap. It has tapered cutting edges, which assist in aligning and starting the tap into an untapped hole. A bottom tap has a continuous cutting edge with almost no taper. This feature enables a bottoming tap to cut threads to the bottom of a blind hole. A bottoming tape is usually used to cut threads in a hole that has already been partially threaded. This is because the tapered end of a bottoming tap is too short to successfully start into an unthreaded hole.
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