Separator and feed screw for a grinding machine

A grinding machine comprising:

• a first feed screw configured to rotate within a first head to advance material in a downstream direction;
• a first center pin rotatable with the first feed screw and a first knife assembly rotatable with the first center pin;
• a bushing configured to receive the first center pin and rotationally support the first center pin;
• a first orifice plate arranged on the bushing and configured discharge a first portion of the material through an outer section and a second portion of the material through an inner section;
• a second head coupled to the first orifice plate;
• a second feed screw coupled to the first center pin and configured to rotate within the second head, the second feed screw configured to receive the second portion of the material through an ingress end, wherein an axial face of the ingress end is configured to abut an axial face of the bushing such that the bushing acts as a thrust bearing;
• a second center pin coupled to and configured to rotate with the second feed screw and a second knife assembly coupled to and configured to rotate with the second center pin;
• a second orifice plate configured to be axially repositioned along the second center pin, the second orifice plate configured to discharge a third portion of material through a second outer section and a fourth portion of material through a second inner section;
• and
• a mounting ring coupled to the second head by mating engagement allowing linear adjustment of the mounting ring relative to the second head,
• wherein the second head includes a stop shoulder and the mounting ring includes a lip, and
• wherein linear adjustment of the mounting ring is configured to axially position the second orifice plate to abut the stop shoulder and the lip.