Method for clamping shaft part and special cylindrical jig

The invention discloses a method for clamping a shaft part and a special cylindrical jig, wherein the method for clamping the shaft part can ensure the processing precision. The method comprises the following steps: 1. adjusting a support center of a center frame and a rotating center of a chuck and keeping coaxial; 2. clamping the axial end of the shaft part on the chuck, axially sleeving and suspending a shaft body of the shaft part in the cylindrical jig and rotatably supporting the outer cylindrical surface of the cylindrical jig on the center frame; and 3. leading the shaft part to drive the cylindrical jig to rotate on the center frame by the rotating chuck and adjusting and fixing the radial opposite position between the cylindrical jig and the shaft body of the shaft part according to the radial jump of an excircle of the cylindrical jig during rotation. The invention also provides the cylindrical jig used by the method, comprising a cylinder body, wherein the cylinder body is cylindrical on the surface and is opened at both ends; and a radial support positioning device is arranged in the cylinder body.