... Machinery Co., Ltd. Was established in 1998,located in Cangzhou which is in the industrial zone of Cangzhou city ,and ... metal sealed(HJ) rubber sealed(HA) not sealed(W)11,Formation: soft formation, soft to medium hard ... 6-17 1/2(inch)Type tricone bits,steel tooth bits, PDC bitsApplicable water well,oil field, construction, ... ”)212.7mm(8 3/8”),215.9mm(8 1/2”),222.2mm8 3/4”) 241.3(9 1/2”),244.4(9 ...