Unlike a hammer mill in which a series of hammers strike and break the material until it passes through a bed screen, the screen classifying cutter employs re-sharpenable solid stainless steel cutter blocks that are welded without seams in a staggered array, and cut against two bed knives — one on the upswing, one on the downswing. With the variable speed motor, the plant can run the cutter at 1,500 rpm to produce particles down to 1/16 in. (1.6 mm), or at 1,200 rpm for particles down to 3/16 in.