| 摘要 |
PROBLEM TO BE SOLVED: To provide a throwaway tip capable of exhibiting a sufficient cutting property at a wide cutting area by providing two kinds of breaker projection capable of appropriately carrying out cutting at each area of finishing cutting and intermediate cutting of a general steel material. SOLUTION: A cutting blade 6 is formed on a ridgeline of upper and lower surfaces 2 of a throwaway tip of a polygonal flat plate shape and a breaker groove 11 is formed on an inner side of a land part formed along the cutting blade. A first breaker projection 13 in which a projection of a boss surface 5 formed on a center part of the upper and lower surfaces extends toward a nose part 7 is formed and a second breaker projection 16 is formed at a position symmetrical to a bisector of a nose part in a plane view. The second breaker projection extends from an inclined surface 10 continuing to the land part near the nose part to an end of the first breaker projection and is formed to a recessed shape 17 along a straight part of the cutting blade.
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