This screw secures the plough body to the frame beam at the specified mounting point. It passes through the leg and into the threaded boss on the beam, clamping the assembly against the shear forces generated during tillage. A loose or missing screw allows the body to shift, causing uneven furrow depth and accelerated wear on the adjacent components. The screw is machined to the original thread profile so it seats fully without cross-threading the boss. On reinstallation, clean the threads and torque to the value specified for the plough model.