(1) When measuring, support both ends of the journal on the ball carrier. Limit the amount of shaft runout to 0.10mm before measuring. (2) The shaft along the length of the bisect a number of measurement section, the measurement point surface must be selected in the absence of burr, pitting, blisters, pits smooth shaft segment. (3) The shaft end surface is divided into 8 equal parts as the measuring point, the starting "1" is the key point of the keyway on the shaft, and the measurement record should be consistent with these equal parts. (4) Place the dial indicator on each measuring position in the axial length. The measuring rod should be on the vertical shaft surface. The center should pass through the shaft center. Adjust the small pointer to the middle of the measuring range. Adjust the large pointer to "0" or "50" , Slowly rotate the shaft for 1 week, each dial indicator should return to the starting value. Otherwise, identify the reasons, then adjust to meet the measurement requirements. (5) Measure and record each dial indicator point by point. According to the record, calculate the sloshing value of the inner shaft of the same section, and take the value of 1/2 as the bending value of each section. (6) The same direction along the axial length of the cross-section of the bending value of the drawing point method drawn in Cartesian coordinates, according to the measured bending value and connected to the bitmap into two straight lines, the intersection of two lines for the axis of the maximum bending point .