A tap is a tool for female thread cutting. A taps is manufactured in the form of a screw with straight and helical grooves, which form cutting edges. The operating principle of the tool is as follows: the back tart of a tap is fixed in the tap holder, and the operating part of it is inserted into the orifice, wherein the thread is tapped by rotating the tap holder using translational motions. The main part of a tap includes a cutting part and a gauge part. Its back part has a relief form (non-round shape) to prevent rubbing against the workpiece. When cutting coarse pitch threads, several taps with various pitch are often used (depending on the required accuracy and material used in any part of the workpiece). Taps may be used for closed and open holes. Taps may be used for operations on drilling, or lathe machines, or complex machining centers. Such taps are called machine taps. There are also manual taps.