| 摘要 |
Two peripheral cutting edges (4) are positioned at the sides of the drill head (1) between two grooves (3), which are connected to the shavings disposal groove (12). Two cutting edges (8,9) are joined in order to form a centering part (6) with a centering crest (7). The specific design of the drill head (1) facilitates an extension of the life span of the tool, increases the speed of drilling and ensures a precise centering during the drilling process. |
