Apparatus for machining hard tissue

An apparatus for removing material from the surface of hard tissue, including: a housing (16) having: a hole (18), wherein said opening has a first segment (20) having a first diameter, a second segment (22) having a second diameter, and a third segment (24) having a third diameter, whereby said second segment (22) is positioned between said first segments (20) and third (24) and said first and third diameters are greater than said second diameter; and wherein said segments are generally coaxial; a gear (30) positioned within said first segment (20) of said housing, said gear teeth gear (48) and an axial bore extending therethrough; a support assembly (34) including a body (62) having a first portion (94) positioned within the second segment of said housing, and a second portion (68) positioned within the third segment of said housing, wherein said second portion said body is dimensioned so as not to pass through the second segment (22) of said housing (16), and a movable member (64) within said body, rotatable said movable element relative to the body and has a channel (70) extending therethrough; a hub gear (36) having a first end (54, 56, 58, 32) is positioned within the gear opening (70) and the channel of the movable member of the bearing assembly, said gear hub (36 ) an enlarged portion (52) adjacent said first end, wherein said enlarged portion is sized so as not to pass through the channel of said movable member of the bearing assembly, a first portion (54) adjacent said enlarged portion, wherein said first portion is adapted to connect with the movable element of the support assembly so that the two will rotate together, a second portion (56) adjacent said first portion adapted to connect with the engaging hole so that the two rotate together; a third portion (58, 32) adjacent said second portion is dimensioned so that not pass through the gear opening and further wherein the apparatus takes power and transfers it approximately 90 °.