With hammers fixed to a disc of 1.5" diameter, through which passes a shaft being revolved at 3000 RPM. The hammers are enclosed in a drum, the sides and upper surface of which are roughened. The inner surface is undulant. The lower part of drum is made of chrome plated brass and is detachable so that different mesh screens (Sieves), i.e coarse, medium or fine can be easily placed.