... Steel)Including:Drill rods with Shank H22x108mm,(6,7,11,12 degree taper) taper rods in most ... button bits, cross type bits and chisel bits with(6,7,11,12 degree taper).Bit diameter:28mm- ... 57mm.3.Extension drilling toolsButton bit, face design :Flat face, drop centre, Normal and ... U85,U92,U94,U95,U118 And coal bolting bit and coal bolting rod.6.All kinds of casing ...