Abstract: An outer sleeve of a rotary table deck bushing has an axial passage extending therethrough and within which is disposed an inner core, which has an axial passage extending therethrough to receive a drill string of a drilling tool. The inner surface of the outer sleeve and the outer surface of the inner core have cooperating bearing races to form raceways within which are disposed ball bearings to rotatably support the inner core within the outer sleeve. Each of the raceways communicates with an access passage extending through the outer sleeve to enable ball bearings to be supplied to the raceway and removed therefrom. The outer sleeve supports a slidable key for blocking each of the access passages when the slidable key is in its blocking position. The slidable key is retained in its blocking position on the outer sleeve by a set screw.

Abstract: A drill bit sub, which has a drill bit with three equally angularly spaced cutters releasably threaded into its bottom surface, has its lower portion reduced in diameter. A collar is welded to the uppermost portion of the lower portion of the drill bit sub and has its lower surface formed at an angle to its longitudinal axis. A protective sleeve, which is a hollow cylindrical metal tube, is removably mounted on the lower portion of the drill bit sub and has its upper surface at the same angle as the lower surface of the collar. The protective sleeve has three equally angularly spaced wear strips, which are substantially aligned with the three cutters on the drill bit. A first break out ring is mounted between the bottom of the protective sleeve and a support surface on the drill bit so that the drill bit bears against the bottom of the first break out ring.

Abstract: A drill section includes a hollow tube having a reduced portion of a box disposed in each end. Each box is welded to the hollow tube by a circumferential weld extending around an angled portion connecting the reduced portion of the box to a portion of the box having the same outer diameter as the hollow tube. There preferably is welding of the reduced portion of the box to the hollow tube through three equally angularly spaced slots at each end of the hollow tube. A break out ring is disposed on a threaded pin of a tool joint between the box, which has a threaded recess extending inwardly from its end to receive the threaded pin to attach the tool joint to the box, and an annular surface of the tool joint. A protective sleeve on the box has an annular end surface at the same angle to its longitudinal axis as an annular end surface of a collar, which is welded to the box, and held thereagainst by the tool joint attached to the box.

Abstract: A drill bit sub, which has a drill bit with three equally angularly spaced cutters releasably threaded into its bottom surface, has its lower portion reduced in diameter. A protective sleeve, which is a hollow cylindrical metal tube, is releasably attached to the lower portion of the drill bit sub so that three equally angularly spaced lugs are at specific circumferential positions relative to the cutters. The lugs engage three equally angularly spaced wear strips on a wear strip support, which is mounted on the lower portion of the drill bit sub below the protective sleeve, so that the wear strip support rotates with the drill bit sub. The drill bit bears against the lower end of the wear strip support when the drill bit is mounted on the drill bit sub. The specific positions of the lugs on the protective sleeve align each of the three wear strips with the maximum outer protrusion of one of the three cutters on the drill bit.