This rotary chopper knife is the cutting element mounted on the chopper drum inside the straw chopper assembly. It severs crop material against a stationary shear bar as the drum rotates, reducing straw length for uniform field distribution. The knife is a flat, replaceable blade with a mounting hole at one end; it is secured to the drum by a bolt and must be torqued to the specified value on installation. A dull or chipped knife produces ragged cuts, increasing power draw and leaving longer, uneven straw fragments. Using a knife of the correct thickness and hole geometry ensures it seats flush against the drum face and maintains the proper clearance to the shear bar.