Abstract: A novel cooperative blade construction for the rotor and bed knives of a size reduction machine such as a granulator and the like wherein each of the blades are of an overall chevron configuration so as to form a generally trapezoidal opening therebetween. As the blades progressively move past each other, the height of the trapezoidal opening is reduced such that articles to be granulated are initially contacted at opposed laterally spaced points on opposite sides thereof such that articles are clamped and progressively cut with a minimum of energy consumption, noise and fines production. The generally centrally located peaks of the rotor blades and the bed knife blades are also arcuately displaced away from a radial plane passing through the opposite side portions. The blades progressively move past each other while maintaining an equal cutting gap therebetween.