Abstract: It’s more difficult to obtain the evaluation result of aperiodic spindle error motion in single circle than of work- spice roundness. The evaluation model of aperiodic spindle error motions in single circle is provided based on the analysis of the definition and the observation of spindle ideal axis. For the model, the new set can be dealt with different evaluation method based on the computer, after the spindle error motions set transformed. Then the uniform evaluation criterion of minimum zone reference circles method is established, and also the effects surface uniform evaluation criterion. It’s convenient to obtain the evaluation result by minimum zone reference cir-cles method or maximum inscribed circle method or minimum circumscribed circle method, on the base of the two criterions. Moreover the appreciation precision is improved greatly, and also the appreciation efficiency.

Key words: Error analysis, Error evaluation criterion, Spindle error motion