Abstract: An underwater pelletizer for cutting extruded plastic into a flow of liquid is disclosed. The pelletizer includes a cutter hub (90) carrying at least one cutter blade (96), a cutter shaft (60) for rotationally driving the cutter hub, and a flexible torque converter (80) for connecting a motor to the cutter hub. In one embodiment, the torque converter has a first set of bushings (82) that is fastened to a face (98) of the cutter hub and a second set of bushings that is fastened to a face (64) of the cutter shaft. The disclosed pelletizer has a shaft extension (20) configured to engage a motor shaft, the shaft extension having an outer diameter having formed thereon a splined portion (38) and first (26) and second (28) sealing surfaces. A disclosed motor adaptor (40) has a seal surface (44). A water chamber plate (50) may also have a seal surface (52).