Rotary drag bits.

摘要

A rotary drag bit (11) has cutters (19) rotatably mounted to fixtures (21) with journals. The cutters (19) are constantly forced to rotate or precess by the interaction between the earth formation and the cutter (19). The cutters (19) are fixed in skewed or offset positions on a cutting face (17) of a rotary drill bit head (11). These cutters (19) act as drag or shear cutters when they are operated in an earth formation.