| 摘要 |
PROBLEM TO BE SOLVED: To provide a tip for a drill for simultaneously satisfying chip disposal of a central edge and an outer peripheral edge even for tough material easily discharging thick chips. SOLUTION: The tip 1 for the throw-away type drill is in a positive type in a substantially parallelogram flat plate shape, and a breaker groove 6 in the tip 1 for the throw-away type drill is formed more deeply and widely in the outer peripheral edge 2B than the central edge 2A. A negative shaped land 5 is provided adjacently between the outer peripheral edge 2B and the breaker groove 6, and the central edge 2A is not provided with a land 5 and is connected directly to the breaker groove.
|
