This nut secures fasteners in the header, threshing mechanism, and drive system of the host machine. It is used where a hardened fastener is required to maintain clamp load under the vibration and cyclic loads common in forage and harvesting equipment. A nut that loosens in these locations can allow driveline components to shift, leading to misalignment or accelerated wear on mating parts. The manufacturer specifies a hardness class of 10.9, which provides the tensile strength needed to resist deformation under torque without galling the threads of the mating bolt. On reinstallation, clean the threads and torque the nut to the value specified for the application.