This mounting bar secures the cutterbar knife head to the cutterbar beam on a grain harvester header. It positions the knife head so the reciprocating knife registers correctly against the stationary ledger plates. A loose or worn bar allows the knife head to shift, causing misalignment that accelerates wear on the knife sections and ledger plates. This component is machined to match the original mounting geometry, so the knife head sits at the correct height and angle without shimming. When reinstalling, clean the beam face and tighten the fasteners to the specified torque.