... are chisel bits, cross bits, buttons bits, DTH bits with high, medium and low air pressure, symmetric drilling tools, eccentric drilling tools, standardized ... Chisel Bits / Cross Bits / Button Bits Diameter---28mm,30mm 32mm,34mm,36mm,40mm,42mm,44mmThread Drill Bits---Diameter: 51mm to 127mmThread Type ... 3) Face ShapeConvex---Suitable for soft rock ( less than 1033.5bar)Concave---Suitable for ...