Bohrer

摘要

The present invention relates to a drill (10), preferably for metal cutting, including a substantially solid shank (12) having a first tip end (14), including at least one cutting edge, a second opposite end (16) and an intermediate portion (20) located between the first tip end (14) and the second opposite end (16), a number of flutes (22) corresponding to the number of cutting edges, said flutes (22) extending helically from the tip end (14) to the intermediate portion (20) of the shank (12). The cross-sectional area of the flutes (22) increases gradually from the tip end (14) to the intermediate portion (20) and the helix angle ( alpha ) decreases gradually from the tip end (14) to the intermediate portion (20).