Thread taps are the tools used to cut the female portion of a mating pair of metal fasteners, while another device called a die is used to cut the male portions. So taps are used to cut nuts and dies are used to cut bolts. Taps can also be used to cut threads into a hole, so that they will receive a bolt more effectively. Many types of thread taps exist with a variety of different uses.
Straight Flute Taps
Straight flute taps are the most inexpensive and simplest tap available. They are designed to be used by hand. The threads on these taps are straight, giving the tap's surface a ribbed appearance.
Gun taps have straight flutes and angular cutting faces on the very end. These angular cutting faces help to propel the pieces of material in front of the tap they will not interfere with the cut of the taps. Therefore, this sort of tap gives a very close, exact cut.
Spiral Flute Taps
Spiral flute taps are designed to be used with machines. They work best when used on aluminium and soft steels. The shape of the taps allows the chips to be propelled out of the hole, so that the threading will be deeper and more precise.
Spiral Pointed Taps
Spiral pointed taps are designed for high-speed production. They have one leading flute that is ground at an angle to the access of the tap. Like gun taps, spiral pointed taps also propel chips forward of the tap so that the threading will not be affected.
Pipe taps come with either parallel threads or taper threads. They are shorter than regular taps and can be used either with a machine or by hand.
"Thredflo" taps are a specialised type of tap intended to be used for the machine tapping of material used in duct construction. "Thredflo" taps don't have the same built-in chip management measures, but instead have special lobes which cause the material to come out as a roll.
Long Shank Machine Taps
Long shank machine taps, just like their named suggests, are longer than the average type of tap. They come in different sizes and types.
Machine NIB Taps
Machine NIB taps are used especially for nut manufacture. They are made to ensure that the shape of nut threads will be absolutely perfect.