An agricultural vehicle includes a chassis and a header carried by the chassis. The header includes a cutterbar with at least one cutting unit. The at least one cutting unit includes a rotary driver； a rotatable disc coupled to the rotary driver； at least one knife mount coupled to a disc surface of the rotatable disc and including a locking portion biased toward the disc surface； and a knife locked in at least one direction by the locking portion, the knife defining at least one cutting edge.
