... 517 8 1/2" IADC 517 Kingdream hard rock drill bits HAS series for oil well 1.Introduction about us: ... kinds of rock bits, such as PDC bits, TCI bits, rock bits, tricone bits, single cone bits, steel tooth bits, insert tooth bits, roller bits, drill bits, drilling tools etc ... 8”),149.2mm(5 7/8”)152.4mm(6”),155.5mm(6 1/8”),158.7mm(6 1/4”),161. ... (6 3/8”),165.1mm(6 1/2”)190.5mm(7 1/2”),193.6mm(7 5/8”),200. ...