| 摘要 |
A hard metal cutting bit is useful both for rough cutting and for finishing, and comprises a polygonal member having parallel opposite main faces, and on at least one of the main faces a fillet that extends continuously about the edge of the main face, the fillet being concave and of greatest depth and width mid-way between the corners of the bit and of the least width and depth at the corners of the bit. A first chip breaker on the main face is next to the fillet and is of least width and depth mid-way between the corners and greatest depth and width adjacent the corners of the bit. A second chip breaker is next to the first and spaced by the first chip breaker from the fillet, and is discontinuous and concave and of greatest depth and width mid-way between the corners and terminates adjacent the corners. |
