Abstract: A forage harvester having a cutterhead with underbeveled knives thereon is disclosed. In a preferred embodiment, each knife has a lateral cross sectional configuration closely resembling an isosceles trapezoid with the initial cutting edges formed by the sides and the longer base thereof. Sharpening of the knife results in the formation of a new cutting edge on the side which is closer to the shorter base than the previous cutting edge. The method of performing the sharpening operation is also disclosed.

Abstract: An improved shear bar for cooperative interaction with the cutterhead of a forage harvester is disclosed. The shear bar structure includes a multiplicity of elongate rib-like projections on the top surface thereof extending lengthwise away from the cutterhead. A scraper for the lower infeed roll is also disclosed to have similar projections on the top surface thereof.

Abstract: A forage harvester having a rotatable cutter head coacting with a shear bar is provided with a grinding wheel which is power driven and adapted to be moved longitudinally along transversely extending guide means adjacent the circumferential outline of the cutting edges of the knives of the cutter head while the grinding wheel is rotating. When the guide means is in one position, the grinding wheel is positioned to sharpen the cutting edges of the knives and, when one end of the guide means is shifted to a second position, the grinding wheel will be positioned to grind bevelled surfaces of uniform depth and width along said knives rearwardly of the newly sharpened cutting edges thereof.