Hex Nut Manufacturers introduces three categories of lock nuts:

1. Use two same nuts to screw on the same bolt, and add a tightening torque between the two nuts to make the bolt connection reliable.

2. The special lock nut needs to be used together with a kind of lock washer. The special lock nut is not a hexagonal nut, but a middle-round nut. There are 3, 4, 6, or 8 gaps on the circumference of the nut (depending on the size of the nut and the product series of the manufacturer). Several notches are not only the focus of the tightening tool but also the entry point of the locking washer.

3. Drill through threaded holes from the outer surface of the nut to the inner thread surface (usually two, distributed at 90 on the outer surface), used to screw in small diameter countersunk screws, the purpose is to apply a thread to the thread The centripetal force prevents the lock nut from loosening. A lock nut with better quality on the market is inlaid with a small copper piece on the inner surface of the nut that is consistent with the thread of the lock nut to prevent the radial jack screw from directly contacting the locked thread and damaging the latter. . This kind of lock nut has gradually begun to be applied in the occasion of the shaft end locking of rotating parts, such as the anti-loosening of the bearing at the mounting end of the ball screw.