This header control knob mounts on the operator interface inside the cab, where it connects to the linkage that adjusts the header's working position. Turning the knob moves the mechanical cable or rod that raises, lowers, or tilts the header assembly. A worn or stripped knob leads to imprecise adjustment, causing the operator to overshoot the desired header height. The manufacturer machines the internal threads to match the original linkage stud, so the knob seats without cross-threading or play. On installation, ensure the threads are clean and the knob is hand-tightened until it contacts the stop; do not use a tool to overtighten.