... rock bit,tri-cone drill bit ,3 cone bits,rotary bit, TCI tricone bit,PDC drill bit ,diamond core bit,bicenter bit,single ... cone bit , reamer bit,down hole opener,hole enlarger,drag bit,button bit and drilling equipment for ... 1/2539-83360-40medium hardHard Dolomite, Limestone, Hard Sandy, Rock etc.595.2~174.63 3/4-6 ... mm with 3 1/2" REG Pin for Hard Rock