Abstract: A machine for chopping polymers, and in particularly elastomeric materials such as tires, into uniform small size particles through the use of a rotating cutting head having teeth that have side cutting edges generally perpendicular to their outer end edges, which are parallel to the axis of rotation, and interfit with stationary teeth formed in complimentary shape. The cutting head is used in combination with a material infeed mechanism that maintains a steady, positive feed of material to reduce the elastomeric material into uniform small chunks that can be used for fuel, or otherwise more readily disposed than the present large size tires or similar articles.