... button bit, rock drill bit,Retrac Button Bits,taper drill bit,tapered drill rods,taper button bit thread ... button bit, rock drill bit,Retrac Button Bits,taper drill bit,tapered drill rods,taper button bitDiameter :40 ... , T51, T60, ST58(T)Bit Body: StandardBit Face: Flat, Concave, ConvexThe threaded button bits can be used in all rock formation, they ...