Abstract: Material is mechanically removed from the cut-out extremities of the graft holder (1) and graft (13) by a tool fitted with two parallel milling cutters (3, 4) of different thickness, in which the inner face of the milling cutter of smaller thickness (3) lies in the plane passed by the longitudinal central axis (X-X) of the graft holder and of the graft, so as to create two matching longitudinal hollow seats (5, 6) and longitudinal extensions (14, 15), where the extensions of one portion end up being exactly capable of interpenetrating the hollow seats of the other portion, and the longitudinal central axes (X-X) of the graft holder and of the graft turn out to be coincident.