Abstract: Much better control of the grind of a rotary mill and much more uniformity of grind of the mill is achieved by better control of air flow through the mill, provided by making the milled product collecting pan of the mill air-tight and regulating the amount of in allowed to escape from the pan. The apparatus of the invention includes a housing in which are mounted two discs in spaced, confronting axial alignment, each disc having extending therefrom toward the other disc concentric rows of teeth. The rows of teeth overlap so that alternating rows of radially spaced, interposed teeth are formed. One of the discs is adapted to be rotated in relation to the other disc and grain to be milled, along with any air flow through the mill, is introduced through an inlet to the area between the discs inwardly of the innermost rows of teeth. An outlet into a substantially air tight collecting pan is provided for the milled material after it passes radially outwardly through the interposed row of teeth.

Abstract: A safety handle is provided for manually rotating a motor shaft for a stone grinding mill. One end of the handle is curved to encompass a portion of the shaft periphery. A hook at the end of the curved portion fits into the keyway of the shaft. The handle arm extends radially from the shaft with a hand grip at the end opposite the curved portion. When torque is applied to the handle in the direction of normal motor rotation, the curved portion and hook grip the shaft by rotational leverage and transmit the torque to the shaft. If the motor is inadvertently started with the handle on the shaft, inertia and gravity will cause the handle to disengage and roll off from the shaft to prevent damage and injury. The hand grip is attached to the handle so as to allow only manual rotation of the shaft in the normal motor direction. Alternately, the handle is bent transverse to its longitudinal axis to extend outward from the motor and thus enable rotation only when mounted properly on the shaft.