... precision. 2.Unique design. 3.Easy operation. 4.Good quality oil drilling rig AVT-kg930a1.Diameter of hole80-115mm 2,Optium ... optimize and upgrade the hydraumatic system , the part of drill boom and part walking so on . It has better function than ... carriage swing angleLeft100°,right45°,total 145°Drill boom pitch angleBlow 50°,elevation25°, total 75°Drill boom pitch swing angleLeft45°, right90°, total ...