Drill has shaft with flutes and tapered tip section with variably spaced cutting teeth

摘要

The drill (10) has a shaft (12) with at least one drill flute (14,15) which, on a tapered section of the drill reduces in size spirally. The reducing size section of the flutes carry cutting teeth (18). The spacing of the teeth is larger in an inner section of the drill shaft then in an outer section. The teeth can be radially offset outwardly.