AN lock nuts are used to locate bearings onto a shaft. They have inch threads and four, equally spaced slots around their circumference to accommodate a spanner. They should be locked by a lock washer to prevent unintentional loosening. AN lock nuts can be reused, provided they are not damaged.
Avantages
Simple, stable and reliable fastening element
Easy to install and remove
Reusable with a new locking device
Require a keyway in the shaft or adaptor sleeve thread