No cutting will occur when working. The thread profile is formed by extrusion with a tap. It is especially suitable for copper alloys and aluminum alloys with low strength and good plasticity, and can also be used for materials with low hardness and high plasticity such as stainless steel and low carbon steel. The surface quality of the thread extruded by the extrusion tap is good, forming a dense cold hard layer, which can improve the strength and wear resistance of the thread. The productivity of this processing method is also high. The ten arcs at the top of the extrusion tap can bear increasing load. Experiments show that the tip of the tap begins to wear after 2000 screw holes are extruded. The life of the faucet is very long, which is about 10 times that of the ordinary faucet. The external structure of extrusion tap is similar to that of ordinary tap, including extrusion cone, scale part and handle. The extrusion cone has a complete cone thread, which is used to complete the main extrusion task. There is a cylindrical thread on the calibration piece, and the thread extruded by the extrusion cone is shaped. The cross section of extrusion tap is triangle with curved edge, and large diameter tap can be made into quadrilateral or prism with curved edge. At present, extrusion taps are mostly used for threads below m 10, and are generally not suitable for processing brittle materials such as cast iron and bronze.