This mounting plate secures the concave section inside the threshing unit of a grain harvester. It holds the concave in position against the threshing drum, maintaining the correct clearance for efficient separation of grain from the straw. A worn or deformed plate allows the concave to shift, which reduces threshing efficiency and increases the risk of damage to the drum and concave assembly. The plate is an original component, machined to match the locating surfaces of the concave frame so that no shimming or adjustment is needed during installation.