This chain link lock secures the connection between adjacent strands of the threshing-mechanism chain. It is a formed wire clip that snaps over the link pins to prevent the chain from separating under load. A missing or worn lock allows the chain to open at the master link, which can cause the chain to derail and damage the sprockets or the threshing drum. This original component is formed to the same wire diameter and gap dimensions as the original assembly, so it seats fully on the link without requiring additional bending or adjustment.