a rock bit for a down - the - hole drill provides auxiliary flow paths for flushing the working face of the drill bit to facilitate the removal of cuttings and debris through peripheral troughs in the drill thereby significantly reducing the abrasive effect of the cuttings and debris on the bit body . the exhaust fluid is supplied to the working face of the drill bit through several delivery channels spaced equidistantly about the periphery of the drill head where a first set of delivery channels are disposed at acute angles to the central axis of the drill bit and a second set of delivery channels are interposed directly between the central bore of the drill bit and the working face .