... rotary drilling rig High efficiency; Quick tools switching system; No noise,no sound operation; CE certificate. SD series multifunctional hydraulic rotary drilling ... 22870mm* hole diameters: 750mm,1000mm,1200mm,1500mm,2000mm,2500mm* drilling depth:35m,44m,56m,68m,77m,81m etc. Major components ... : friction type kelly bar and inter-locking kelly bar;* Drilling bit: auger bit,cylindric bit,rock core bit.