W lock washers are locking washers used to secure AN and N lock nuts on a shaft or pull bush and prevent inadvertent loosening. The lock washers engage in a keyway in the shaft or thread of the pull bush. They secure the nut in place when one of the tabs of the washer is bent into one of the locking grooves in the outer diameter of the locknut. A new corresponding lock washer must be used each time the lock nut is fitted.