... machine, such as Atlas Copco, Sandvik, In We are a professional company which is specialized in making and researching on drilling ... of the products.Tapered Drill BitType --Chisel Bits / Cross Bits / Button Bits Diameter---28mm,30mm 32mm,34mm,36mm,40mm,42mm,44mmThread ... . Integral Drill Rod---H19/H22, Diameter---20mm - 42mm. T51 Thread button bits