Lock nuts are used to locate bearings onto a shaft. Additionally, they can be used to mount bearings with a tapered bore onto tapered shaft seats and adapter sleeves, and to dismount bearings from withdrawal sleeves. Lock nuts are also frequently used to secure gears, belt pulleys and other machine components.

Lock nuts have to be secured to prevent unintentional loosening by:

a locking device that engages a keyway in the shaft or key slot in the adapter sleeve, or

a locking mechanism integrated in the nut

When choosing or replacing a lock nut, there are a number of factors that should be taken into consideration. They include, but are not limited to:

Space  axial and radial

Shaft rotation  one or both directions

Axial loads

Dynamic behaviour of the application

Cost and downtime of machining keyways in shafts vs. other locking methods

Ease and frequency of assembly and disassembly

Precision