Abstract: The cutter used with a cylindrically shaped die plate means on a thermoplastic extruder is rotatable about the axis of the die plate and has a plurality of radially projecting blades that extend longitudinally and sweep across the downstream face of the die plate means as the cutter rotates severing extruded heat-plastified material into pellets. The blades form continuous longitudinal channels within which the pellets collect as the cutter rotates. The cutter is enclosed to permit pellet treatment fluid to flow longitudinally over the cutter and flush the pellets from the channels as soon as the pellets are severed. The die plate means comprises a pair of nested die plates mounted for selective positioning relative to one another. In one relative position, the orifices in the plates are essentially aligned to offer minimum constriction to the extrusion of heat-plastified material through the orifices.