drill bit,drill bits,rock drilling tools,rock drilling tool,Button bits,rock drill,threaded,tapered,drilling tools, 1. Button bits ... on with different degree taper) Thread Button Bits (33mm, 35mm, 45mm to 89mm, 102mm and so ... , Cop44, Cop54, MACH30, MACH40, MACH50, MACH60 etc4 Tapered Drill RodShank h22x108mm, (6, 7, 11, 12 degree taper) ... tight tolerances and controlled straightness. Drill bit