| 摘要 |
<p>This tool is of the type comprising at least two helical flutings defining lips with helical cutting edges progressing from its tip to its body. It is provided, coaxially with its axis of rotation and starting from its tip, with at least one cone 2 with cutting edges forming an angle of 118 DEG , followed by a frustoconical part 3 with cutting edges having an apical angle of a value lying between 60 and 90 DEG , itself extended by a cylindrical bearing surface 12 of larger diameter than it and comprising cutting edges at least in its end face 14. <IMAGE></p> |
