| 摘要 |
The hollow drill tool (1) has a hollow-cylindrical support body (2) and cutting segments (4) which consist of an embedding material and a diamond grain (9) held in the latter. The surface layer (7) of the cutting segments (4) which is remote from the axis of the support body (2) has a higher concentration of diamond grain compared with the remaining area of the cutting segments (4). This guarantees the production of a large number of drill holes of high diametral accuracy. <IMAGE> |
