| 摘要 |
The drill bit comprises a first removable cutting tip (4) with a cutting edge of circular shape arranged in a housing made at the end of a first helical groove (2) and an interchangeable cartridge consisting of a second removable cutting tip (5) with a cutting edge of rhombic shape housed in a support (9) itself removably fastened by means of a screw (10) into a housing made at the end of a second helical groove (3). <IMAGE>
|
