A mill head for replaceable attachment to a base so as to collectively form a bone mill. The mill head includes: a first opening in which bone stock is introduced into the head； a cutting device that converts the bone stock into bone chips； a second opening through which the bone chips are discharged； and a third opening through which a motor integral with the base is attached to the cutting device. Internal to the mill head are containment rings. The containment rings prevent the discharge of material through the third opening. The containment rings are services the internal component of the mill head on which the cutting device rests.
