Some Bit-Penetration Characteristics In Pink Tennessee Marble

Pink Tennessee Marble was tested for wedge bit penetration characteristics at static and dynamic (10 - 250 ft/sec) loading rates. No significant differences were found within the dynamic range as far as the energy required to remove a unit crater volume and the force used to cause a certain penetration. Under static loading, however, both the energy and the force required were significantly lower. Tests run on bits of varying width indicated that as the wedge bit narrowed to an almost conical shape, the energy used per unit crater volume became considerably lower.