Bone mill including a base and a mill head

There is disclosed a bone mill, said bone mill including: a mill head, said mill head including: a shell, said shell having: opposed and spaced apart top and bottom sections; a longitudinal axis that extends top-to-bottom through said shell; a first opening in the shell top section; a second opening in the shell bottom section; and a third opening in the shell bottom section, the third opening being closer to the longitudinal axis of the shell than the second opening; a cutting device movably disposed in said shell between the top and bottom sections, said cutting device including: at least one cutting feature located between the shell first and second openings configured to cut bone stock introduced into the shell first opening into bone chips so that the bone chips are discharged through the shell second opening; and a coupling feature that is accessible through the shell third opening; and a barrier disposed in said shell around the third opening so as to separate the second and third openings and prevent the discharge of bone chips through the third opening; a base, said base separate from said mill head and having a surface for receiving said mill head shell; a motor disposed in the base; a drive stem connected to said motor so as to rotate upon actuation of said motor; a spindle connected to said drive stem to both rotate with said drive stem to and, while rotating with said drive stem, move longitudinally relative to said drive stem, said spindle including a coupling feature shaped to engage said cutting device coupling feature across the mill head shell third opening so that, when said coupling features engage, said cutting device is actuated upon the rotation of said spindle and wherein said spindle is located between said motor and said mill head cutting device; a biasing member connected to said spindle that exerts a force on said spindle so as to urge said spindle away from said motor and said spindle coupling feature into engagement with said cutting device coupling feature as said spindle is rotated by said motor; and a locking assembly integral with at least one of said mill head or said base for releasably holding said shell to the base in opposition to the force exerted by said biasing member.