Abstract: A wet grinding machine which includes a grinder head, an annular stator mounted on the grinder head, and a rotor rotatably mounted in the grinder head. Shearing blades on the rotor turn inside the stator and sweep across shearing slots in the stator. Each of the shearing slots slopes and overlaps adjacent shearing slots so that each of the blades is constantly addressing an inner edge of at least one of the shearing slots. A classifying screen chamber surrounds the stator but is independent of the grinding machine so that particles of reduced size can pass through the screen to be removed while larger particles are retained and sheared by the rotor blades against inner edges of the slots.