Abstract: A center tube retention system of a down-the-hole tool includes a casing having an inner wall, a feed tube centrally disposed within the casing, the feed tube having an upper end and a tapered outer surface at the upper end, and a tube holder arranged to receive the top end of the feed tube, the tube holder having a tapered inner surface, the tapered surface of the feed tube matching the taper of the tube holder to form a tapered seat. The tube holder is formed as a collet having a plurality of machined slits aligned radially to a central axis of the casing. The slits are arranged to allow the tube holder to expand outward and press against the inner wall of casing ensuring alignment and retention of the feed tube within the casing.

Abstract: A down-the-hole hammer drill having a reverse circulation system which conducts pressurized air downwardly to a lower cutting face of a drill bit. The air travels across the cutting face and upwardly through a central exhaust passage. The air is conducted to the cutting face through longitudinal and lateral passages in the bit which are kept isolated from the environment surrounding the bit so that no appreciable amount of pressurized air can escape, and so that the passages do not become clogged with dirt. The drill bit comprises upper and lower pieces. Upper sections of the longitudinal passages are formed in the upper piece, and lower sections of the longitudinal passages are formed in the lower piece.