| 摘要 |
A drill includes a shank having a tip with two cutting inserts located in a main plane. The cutting inserts have short central cutting edges oriented in a secondary plane. The edges form a pointed center cutting edge for the purpose of entering a workpiece and thereby centering the drill. In the shank two helical flutes are provided, the flutes extending from the tip to the base end. The flutes are located diametrically opposite each other and are separated by two helical lands. The flutes lie in a flute plane that extends at an angle of 90 DEG to the land plane. The secondary plane forms an angle of about 90 DEG to the orientation of the land plane when viewed at the base end of the shank. |
