... or produce according to your request best service earth drilling bit Thread button bits1. Rope thread:R25 R28 R32 ... and Conical. (Threaded R32, R38, T38, T45, T51, bit diameter: 45mm-127mm);Tapered Button Bit1. Taper: degree 4° , ... 7°, 9°,11°, 12°.2. Type: flat bit, cross bit, button bit3. Main bit diameter: 30mm, 32mm, 36mm, 40mm 4.Package: ... used in mining,coaling,metaling and etc earth drilling bit