... , hard rock and any other special formations thread button bits Thread button bits made with high quality of best quality alloy steel ... design: Flat face, drop centre, Normal and Retrac body.Tungsten carbide (Buttons): Spherical, ballistic and Conical. (Threaded R32, R38, T38, T45 ... , T51, bit diameter: 45mm-127mm); (2) Main button bits diameters:R32-45mm, R32-51, R32-64, R32-76,T38 ...