drill bit,drill bits,rock drilling tools,rock drilling tool,Button bits,rock drill,threaded,tapered,drilling tools, 1. Button bits: Tapered button bits (28mm, 30mm 32mm, 34mm, 36mm, 40mm, ... , R25, R28, R32, R38, T38, T45, T51 etc.) Retrac Button bits with different Thread different diameters. 2. Dth bits: From ... -carburized and manufactured with tight tolerances and controlled straightness. Drill bit