| 摘要 |
By press-fitting a cylindrical blank into a die with one of a pair of punches, and at the same time press-fitting small diameter end portions and tapered portions of the pair of punches into both ends of the cylindrical blank while restraining both end surfaces of the blank with cylindrical members movable on the outsides of the punches, the external circumferential surface of the blank is finish molded to the required diameter by the internal circumferential surface of the die and, at the same time, tapered surfaces are formed on the inner circumferential surface in both ends of the blank. The process produces a bushing with its internal surfaces accurately coaxial, and with the external surface accurately formed to the required diameter.
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