When drilling with a drill bit, if the drill bit is deviated, it is easy to break or be uneven; The tapping needle is a tap, and its top and bottom are the same size; When tapping, that is, when screwing, there are many reasons for tooth slip. The most important reason is that the faucet has been used for a long time and the surface buckle has been worn flat. The simplest remedy is: if it is a small number, such as one or two, screw the hole with a new tap. If it is too much, it will be deducted again.