Precise columnar member and method of producing the same

Abstract

The present invention relates to a metallic, precise columnar member having an outer diameter with high accuracy, wherein the columnar member comprises a plurality of flattened thread ridges having a predetermined outer diameter provided on the surface of a metallic columnar blank in an axial direction. The method of the present invention comprises the steps of using rolling to form a plurality of thread ridges on the surface thereof and using rolling or drawing to make the tops of the thread ridges flat.

1 . A precise columnar member comprising a plurality of thread ridges or ring-shaped thread ridges provided on the circumferential surface of a metallic columnar blank in an axial direction and worked to be flat so that the tops of the thread ridges or ring-shaped thread ridges have a predetermined outer diameter.  
     
     
         2 . A method of manufacturing a precise columnar member, the method comprising the steps of: (a) using rolling to form a plurality of thread ridges or ring-shaped thread ridges on the circumferential surface of a metallic columnar blank in an axial direction to obtain a preformed blank; and (b) using rolling or diameter-reducing working to make the tops of the thread ridges or ring-shaped thread ridges of the preformed blank flat to obtain a precise columnar member having a predetermined outer diameter.  
     
     
         3 . The method of manufacturing a precise columnar member, according to  claim 2 , wherein the step (b) is applied to only a part of the preformed blank in the axial direction.