The rotary plastics crusher/grinder is a versatile machine designed to reprocess a wide range of waste plastics, particularly hard plastics. It features a horizontal rotor with plate blades, each equipped with two side cutting edges, mounted in heavy-duty bearing housings on both sides within the processing chamber. The chamber also includes fixed plate blades aligned with the rotary blades. The chamber assembly is constructed from a robust, milled heavy-duty blade, providing exceptional stability and rigidity. This design effectively controls torsions and side sways during high torque loads.