| 摘要 |
A rotatable cutting tool (10) for impinging the earth strata wherein the cutting tool has a tool body (12) with an axial forward end (14) and an axial rearward end (16). A hard insert (30) is at the axial forward end and a retainer (22) is carried by a shank portion near the axial rearward end. The hard insert has an axial forward generally conical tip section (32) that presents a tip surface and has a starting included angle of between greater than about 110 degrees and less than about 140 degrees, a transition section (34) (wherein at least a portion of the transition section presenting a convex shape) that is contiguous with and axially rearward of the tip section, a radially outwardly expanding first mediate section (36) that is axially rearward of the convex section, and a base section (44) that is axially rearward of the mediate section.
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