... years experience in well drilling equipments 1 Specification:Size9 7/8”(250.8mm)IADC632GBearing TypeAir cooling roller bearing bitThread Connection6 ... /2”),193.6mm(7 5/8”),200.0mm(7 7/8”)212.7mm(8 3/8”),215.9mm(8 1/2”),222.2mm8 3 ... 2”),244.4(9 5/8”),250.8(9 7/8”)269.8(10 5/8”),295.3(11 5/8”)311.1(12 1/4 ... 24”)660.4(26”)Available model:Steel tooth(IADC)111, 121,131117,124,126,127,136,137 211,311216,217, ...