Tab Washers can also be known as Locking Washers. These are simple method of ensuring that lock nuts remain securely fastened. The central tab locates in a key-way in the shaft and the nut is fitted and tightened to the correct torque, the washer will now have one of its tabs aligned with one of the slots around the lock nut, this tab is folded over into the slot. Lock nuts are used with lock nuts of the KM and KML series