... .30 years experience in well drilling equipments 1 Specification:Size9 7/8”(250.8mm)IADC632GBearing TypeAir cooling roller bearing bitThread Connection6 ... ”)130.1mm(5 1/8”),133.3mm(5 1/4”),139.7mm(5 1/2”),142.8mm(5 5/8”),149 ... .1mm(6 1/2”)190.5mm(7 1/2”),193.6mm(7 5/8”),200.0mm(7 7/8”)212.7mm(8 3/8 ... ,,617,627,637,737512,522,532,612,622,632,732 7 ISO Certification FAQ(Frequently Asked Questions) 1. How to ...