The first cone tapers out the outline of the thread first, and the second cone makes the thread smoother based on it, so that the screw can be easily screwed in! Hand taps can be divided into groups of three or groups of two, namely head taps, two tapers, and three tapers. Taps in groups of two are commonly used. When using, use the head tap first and then the two tapers. The cutting part of the head cone has a longer slope and generally has 5-7 incomplete tooth shapes; the second cone is shorter and has only 1-2 incomplete tooth shapes. The front cone of the head cone is long for easy guidance; the front cone of the second cone is short.