rock drilling tool,Button bits,rock drill,threaded,tapered,drilling ... T38, T45, T51 etc.) Retrac Button bits with different Thread different diameters. 2. Dth bits: From 115mm, 120mm, ... taper) , Length can be according to customers requests. 5 Thread Drill RodR22, R25, R28, R32, R38, T38 etc ... be according to customers requests. 7. Coupling with different thread for example R22, R25, R28, R32, R38, T38 ...