Deflection tester used procedures for measuring shaft runout, the instrument uses two top positioning shaft parts, the part is rotated, the probe in the radial direction of the tested part directly measure the part diameter runout errors. deflection tester using the rules: 1. deflection tester is a sophisticated detection equipment, the operator must be familiar with the operation of the instrument skills, carefully maintenance, and designate a person to use 2. deflection tester equipment must be kept intact, balanced and reliable equipment should be installed, the rail surface to be smooth, no bump scars, two top concentricity tolerance should be within the range L = 400MM to and (b) to a less than 0.02MM. 3. workpiece detection ago should use L = 400MM test rods and dial indicator deflection device for precision calibration, to ensure that qualified before use.