This bolt secures the flail to the threshing mechanism of a forage harvester or combine. It passes through the flail and the mounting point on the rotor or drum, holding the component in place during high-speed operation. A loose or missing bolt allows the flail to detach, causing imbalance and potential damage to the surrounding housing. The bolt is manufactured to a hardness class that provides the necessary tensile strength for this application. On installation, tighten the nut to the specified torque and use a thread-locking compound if recommended by the machine manual.