Abstract: A ball polishing method includes the steps of rotating one of two plates through use of a rotating mechanism while balls are sandwiched between the plates, pressing one of the two plates against the other plate via a guide slide mechanism for guiding one of the two plates to the other plate by means of a pressing mechanism, and polishing the balls while the pressing force is regulated through use of a pressing force control mechanism. The method is further provided with rotary support means for supporting the rotating mechanism and guide support means for supporting the guide slide mechanism, and at least one of them utilizes hydrostatics. By virtue of this method, a machining pressure can be controlled with a high degree of accuracy, and the accuracy of polishing of balls can be improved.

Abstract: A ball polishing method includes the steps of rotating one of two plates through use of a rotating mechanism while balls are sandwiched between the plates, pressing one of the two plates against the other plate via a guide slide mechanism for guiding one of the two plates to the other plate by means of a pressing mechanism, and polishing the balls while the pressing force is regulated through use of a pressing force control mechanism. The method is further provided with rotary support means for supporting the rotating mechanism and guide support means for supporting the guide slide mechanism, and at least one of them utilizes hydrostatics. By virtue of this method, a machining pressure can be controlled with a high degree of accuracy, and the accuracy of polishing of balls can be improved.

Abstract: In measuring the accuracy of a thread groove of a ball thread formed in a nut by using an electric micrometer, a displacement of one point on each of a pair of flanks of the thread groove is measured along a longitudinal direction of the thread groove, and a pair of measured data sequences are obtained respectively for the pair of flanks. The data elements of the pair of measured data sequences are grouped into a plurality of groups so that each group includes a pair of data elements which are respectively contained in the pair of measured data sequences and which are corresponding to each other. The accuracy in the depth direction of the thread groove with respect to a reference thread groove is obtained on the basis of a sum of the data elements in each group, and the accuracy in the thread axis direction is obtained on the basis of a difference between the data elements in each pair.