Rock Roller Bits: Soft formation rock bits are used in unconsolidated sands, clays, soft limestones, redbeds and shale. Medium formation bits are used in dolomites, limestones, and hard shale, while hard formation bits are used in hard shale, mudstones, cherty limestones and hard and abrasive formations. Rock Roller Bits: Available Ranges: Tungsten Carbide Bits : 3 7/8" â?? 17 ¼" (98.4mm-438mm) Milled Tooth : 3 7/8" â?? 17 ¼" (98.4mm-438mm)
