... on drilling equipments as well, and our dominant products are chisel bits, cross bits, buttons bits, DTH bits with high, ... guarantee the high quality and reliability of the products.Tapered Drill BitType --Chisel Bits / Cross Bits / Button Bits Diameter---28mm,30mm ... 32mm,34mm,36mm,40mm,42mm,44mmThread Drill Bits---Diameter: 51mm to ...