| 摘要 |
A part-spherical surface having a center of curvature at a workpiece axis is surface finished by rotating the workpiece about the workpiece axis and rotating about a tool axis a tool having a body of substantially greater diameter than the workpiece. The tool has an end formed by a part-spherical seat of the same radius of curvature as the workpiece surface, having a center of curvature on the tool axis, and having an outer periphery of predetermined diameter substantially less than the tool-body diameter, and by a generally frustoconical surface centered on the tool axis and having a small-diameter end adjacent and of generally the same diameter as the seat outer periphery and a large-diameter end spaced axially rearwardly therefrom and joined to the tool body. The tool and workpiece axes are tilted relative to each other so they intersect at an obtuse attack angle smaller than 180 DEG and the tool and workpiece are pressed axially together to engage the surfaces together. The outer-periphery diameter and the attack angle are such that when axially engaged a portion of the workpiece surface is not covered by the tool surface and a portion of the tool surface is not engaged by the workpiece surface so that as the tool wears the outer-periphery diameter increases. The tool is replaced with a fresh tool when the outer-periphery diameter increases so much that practically all of the workpiece surface is covered by the tool surface.
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