Tool for lathe machining of slender shaft and mounting method of tool

The invention discloses a tool for lathe machining of slender shafts, which comprises a tool body, the tool body is a cylinder, the diameters of the two sides of the tool body are smaller than those of the middle part, and a plurality of screw holes are formed in the two sides of the tool body; the invention further discloses an installation method of the tool for machining the slender shaft through the lathe. The installation method comprises the following steps that S1, the tool body is installed in a slender shaft workpiece; s2, the workpiece is placed on a lathe to be machined, screws are adjusted, the position of the tool is adjusted, and outer circles at the two ends of the tool are calibrated through metering; s3, a center frame is installed, and the middle of the tool is clamped; s4, the slender shaft is machined; the tool is simple and reasonable in structure, the tool is installed in the middle of the slender shaft, the jumping amplitude of the outer circle of the slender shaft is controlled, a lath