Gantry milling method for inclined large-diameter deep and long hole

The invention relates to a gantry milling method for an inclined large-diameter deep and long hole. The machining method comprises the following steps that an assembly tool is manufactured; inclination angle conversion, wherein the inclination angle of the inclined deep hole of the outer cylinder is converted into a vertical angle through an assembly tool; performing inclination angle alignment verification, namely performing inclination angle alignment verification on the outer cylinder which is clamped on the gantry milling machine for the first time and performing inclination angle alignment verification on the outer cylinder which is assembled on the tool for the second time; aligning the center of the inclined hole; and large-diameter deep and long hole machining is conducted, a super drill capable of being lengthened is adopted for drilling, and cooling is conducted in the drilling process in combination with the cooling mode of a high-pressure cooling system. According to the gantry milling method for