Lock Nut
Lock nuts are used for application where locking elemet is required. Most common items are the nylon insert lock nut or unitorque lock nut. The nylon insert has a nylon ring that compressing around the mating thread to prevent loosening. The unitorque (prevailing torque) lock nut is a form of all metal lock nuts have a top crimp that distorts the threads causing the locking. Keps nuts are designed with a lock washer on the underside of the nut.