| 摘要 |
PURPOSE:To aim at enhancing the finished flatness of a workpiece, by forming a lap plate in a multiple stacked layer structure consisting of a lap surface plate, a base and the like, and by setting the contact dimensions to be less than one-third of the diameter thereof while the lap plate is made to be flexible. CONSTITUTION:A workpiece 1 which is set on a lap surface plate 2 bonded to a base 8 through the intermediary of a backing plate 7, is rotated about the axis 3 of the lap surface plate 2, and is polished in a mirror surface condition by the lap surface having a spiral groove 6. A fixing screw 12 for the base 8 is screwed into a female thread hole 10 formed in the center part of the backing plate 7 and meshed therein with the male thread part of a drive screw 11. Accordingly, when the center side of the lap surface plate 2 is linearly deformed into a concave shape, the lap surface plate is slightly deformed in the axial direction by the drive screw 11 due to the difference in pitch between the drive screw 11 and the fixing screw 12 so as to make the lap surface plate 2 flat in its entirety by means of the backing plate 7. Thereby it is possible to finish the workpiece with satisfactory flatness. |
