| 摘要 |
A rotary cone drill bit (20 and 120)is provided with inserts (70 and 90) and compacts (50 and 150) having contoured cutting portions (66, 166, 72 and 92). The rotary cone drill bit (22 and 122) includes a bit body (26 and 126) having at least one downwardly extending arm (28) terminating in a spindle (40). A cutter cone (30) with a gauge face surface (62) and a plurality of holes (64) formed therein, is rotatably mounted on each spindle (40). A compact (50 and 150) having a cutting portion (66 and 166) with a radius approximately equal to the desired radius for the resulting borehole (100) is press fit into each hole (64) in the gauge face surface (62). A number of inserts (70 and 90) are also installed in the exterior of each support arm (28). Inserts (70 and 90) have a contoured cutting surface with a radius approximately equal to the desired radius for the resulting borehole (100). The contoured cutting portion on both the compacts (50 and 150) and the inserts (70 and 90) may be either domed shaped or cylindrically shaped.
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