This locking washer secures the bale-feeding-system assembly against loosening from vibration during operation. It sits between the fastener head and the mounting surface of the baler's feeding mechanism, providing a positive lock that prevents the fastener from backing off under cyclic load. A washer that has lost its locking grip allows the fastener to loosen, which can introduce play into the feeding-system linkage and cause timing deviations. The manufacturer machines the washer to the original thickness and inner-diameter specification so that it seats fully against the fastener shoulder and the mating face without deformation. On reinstallation, inspect the washer for permanent set and replace if it no longer holds its shape.