Abstract: The rolling cone cutters of a rotary rock bit are held in place on the bit's bearing pins without the use of the conventional ball bearing locking systems. The improved cone retainer includes a groove in the rolling cone cutters that cooperate with plugs or rods extending from the bearing pin. The plugs (rods) are positioned to bridge between the groove in the rolling cone cutters and bearing pins to retain the rolling cone cutters on the bearing pins. Expander rods are inserted through passages in the bearing pins to extend the plugs (rods) into the grooves in the rolling cone cutters and maintain the cutters in the proper position during the drilling operation.