This right-side knife mounts on the cutter bar of a disc mower. It severs crop material at the base as the disc rotates, directing the cut material into the swath-forming path behind it. The knife is secured through its mounting hole and held in place by a retaining bolt; the cutting edge faces the direction of disc rotation. A dull or chipped knife leaves ragged stubble and increases the power draw on the driveline. As an original part, the hole position and thickness match the cutter-bar pocket geometry, so the knife sits flush without shimming. When replacing, inspect the mounting bolt and the cutter-bar pocket for wear.