... for mining applications. 5.Current Main Availability Diameter/InchIADC CODE3 1/2 211, 121, 241, 537….3 7/8 131 ... 241, 537….4 3/4 131, 211, 537, 517….5 1/2 131, 211, 537, 517….6 211, 121, 241, ... 537….……….. ………………………………12 1/2 211, 121, 241, 537….14 3/4 131, 211 ... 26 131, 211, 537, 517…. API standard 12 1/4''steel tooth tricone bi for water well or oil well drillng