... rock etc. Including impregnated diamond core bit, surface-set diamond bit, reaming shells, casing bit, casing shoe bit, corelifter, corelifter case, core barrel ... give optimum penetration rates and bit life, which is required to keep the cost of diamond drilling to a minimum. The optimum ... TNW, ATW, BTW, NTW, NXD3, AX, NX, NXC, AXT, T6H, 4 9/16, NWD4, 412F, SK6L146, TT46, TB56, TS116, CHD101. Please ...