... drilling machine, such as Atlas Copco, Sandvik, Ingersoll- Tapered Drill BitType --Chisel Bits / Cross Bits / Button Bits Diameter---28mm,30mm 32mm ... Suitable for medium-hard rock (1033.5bar~2067bar)Plate ---Suitable for had rock ( more than 2067bar)Drill RodSteel Drill Rod---H19/H22, ... Rod---R25,R28,R32,R38,T38,T45,T51. Integral Drill Rod---H19/H22, Diameter---20mm - 42mm. rock tapered chisel bit