... drilling diameter 3:good quality DTH drilling rig Hammer bits DTH drilling rig Hammer bits are available to fit different sizes and ... seriesDTH hammer BitsProducts DescriptionHammer bits are available to fit different sizes and ... , Concave Face, Convex Face, Step Gauge, Double Gauge, Flat Face type. The shanks can be Cop series, like cop32, cop34, cop44 ...