... scope is four to twelve, the size is 8-1/2”, 9-1/2”, 12-1/4”, 6”, 17-1/2”,4, the Rotary speed is form ... used the featured about TCI&steel tooth tricone drill bits:1. High-strength, high flexibility, high temperature and high wear resistance ... working life. Sizes and types: Size: Common sizes, 6.6-1/2, 7-7/8, 9-7/8, 10-5/8 ... , 12-1/4 Various sizes also can be made to order. Types ...