MB and MBL lock washers are locking devices, used to secure KM, KML and HM .. T lock nuts onto a shaft or adapter sleeve and prevent unintentional loosening. MB .. A is a stronger version of the MB washer. The lock washers engage a keyway in the shaft or adapter sleeve thread. They lock the nut in position when one of the washer tabs is bent into one of the slots in the outside diameter of the lock nut. A new lock washer should be used each time the corresponding lock nut is installed.
