Abstract: A rotary drill bit includes a rotary cutter rotatably mounted on a leg. A radial bearing arrangement and an axial bearing arrangement are provided in an interface between the cutter and the leg. The leg includes a filling opening for enabling cylindrical rolling elements of the radial bearing arrangement to be installed. The cutter includes a radial flange which radially overlaps the radial bearing arrangement to secure the cutter on the leg. The flange, which is disposed axially behind the radial bearing arrangement and axially in front of the filling opening, includes a recess for accommodating the passage of the cylindrical rolling elements. A locking element is disposed in the filling opening for preventing dislodgement of the cylindrical rolling elements. The locking element includes a lip which projects axially forwardly of the radial bearing arrangement. The lip is disposed radially inwardly of the flange and terminates axially behind the radial bearing arrangement.