We are offering a wide range of Concrete Core Drillers. It is equipped with outer regulating safety clutch, double insulation. correct overload protection switch, when the drill is clocked or the twisting force is too strong, it can break off the clutch or the switch automatically and protect the drilling machine. Size 255mm is fitted with an adjustable bracket on its original engineering drilling machine, it can a bore vertically, and also can drill an inclined bore at the angle of 0-90 degree. Its fixed method can adopt vacuum pump to bleed the air, make the cup to the plain of the building, then fixing the rectangle base and the drilling machine on the bolts of the suction cup. then the drilling can be processed. Thus, you can not drill the expansion bolt hole avoid damaging the building.