This plow screw with nut secures the harrow shield to the frame of the tillage machine. The double-beveled cone head sits flush in the shield's countersink, preventing the fastener from protruding into the soil flow. The hardness class 10.9 rating indicates the screw is designed for the high shear loads encountered during primary tillage. A loose or missing screw allows the shield to shift, exposing the frame to abrasion and stone impact. On installation, tighten the nut to the torque specification for a class 10.9 fastener.