This nut secures a threaded fastener on the header or body of a grain harvester. It is a hex nut with a standard metric thread profile and a hardness rating that matches the strength of a corresponding bolt. When properly torqued, it maintains clamp force on the joint it fastens, preventing loosening from vibration during operation. A nut that has been over-torqued or cross-threaded will not hold the assembly securely and should be replaced. On reinstallation, ensure the threads are clean and the nut is tightened to the specified torque value.