A nut is a nut, a part that is screwed together with a bolt or screw for fastening. A component that must be used in all production and manufacturing machinery is divided into carbon steel, stainless steel, non-ferrous metals (such as copper), etc. several types.

　　There are also three types of lock nuts:

　　The first is to use two identical nuts to screw on the same bolt, and add a tightening torque between the two nuts to make the bolt connection reliable.

　　The second is a special anti-loosening nut, which needs to be used together with a kind of anti-loosening washer. The special lock nut is not a hexagonal nut, but a medium round nut. There are 3, 4, 6 or 8 notches on the circumference of the nut (depending on the size of the nut and the product series of the manufacturer). Several notches are both the focal point of the tightening tool and the snap-in of the lock washer bayonet.

　　The third type is to drill through threaded holes from the outer surface of the nut to the inner thread surface (usually 2, which are distributed at 90 on the outer surface), which are used to screw in small-diameter countersunk head screws. The purpose is to give the thread Apply a centripetal force to prevent the locknut from loosening. The better quality lock nut sold on the market is inlaid with a small copper block that is consistent with the thread of the lock nut on the inner surface of the nut to prevent the radial jacking screw from directly contacting the locked thread and damaging the latter. . This kind of lock nut is gradually applied in the shaft end locking of rotating motion parts, such as the anti-looseness of the bearing at the mounting end of the ball screw.