| 摘要 |
The annular cutter (10) of the present invention has a body portion (12) with a plurality of teeth (122) circumferentially spaced about the lower end (20) thereof and a plurality of flutes (24) extending upwardly around the outer periphery of the body portion between the teeth. Each of the teeth (22) has at least two circumferentially stepped cutting edges (32, 34) with the trailing edge being the the outermost cutting edge (34). These two cutting edges are separated by a shoulder (44) which in the preferred embodiment is defined by the bottom wall (30) of the flute (24). This shoulder has a radial clearance (46) adjacent the outermost cutting edge (34) to accommodate the growth of the outermost chip (50) cut by the outermost cutting edge (34) to facilitate discharge of the chips through the flute (24). |
