... Size range from 3 7/8"to 26" Certification ISO and API Oil Rig Drill Bit1. Cutting Structure of this series tricone rock ... speed applications.6.Main AvailabilitySize Bit TypeIn.mm6152.4 4.7,517, 537, 617, 637 6 1/2 165.1437,517 ... .3437, 517,537,617,6379 5/8244.5517,535,5379 7/8250.8517,53712 1/4311.1437, 517,535, 537,617 ...