Roller cone Bits Roller bit is mounted on the bottom ring of the core barrel for cutting an annular ring in hard and extremely hard rock. They come in different diameters. Haoquan roller bits are classified to welded type and replaceable type. Features of Roller Bit: 1. Optimum carbide grade and shape are chosen according to geology. 2. High quality steel with advanced heat treatment technology ensures the good performance of roller bit. 3. Good quality bearing provides high bearing capacity. 4. Reliable sealing system.