| 摘要 |
A process for producing a handlebar stem includes Steps as follows: (1) providing a handlebar stem raw material piece comprising a cylindrical metal tube with a central axis and a thickened open end terminating in a margin and having an outer wall; (2) forming an annular recess from the outer wall in the vicinity of the margin, the annular recess having an outer shoulder and an inner shoulder both perpendicular to the central axis; (3) axially punching the open end of the raw material piece with a punching member to form a flange on the open end that is perpendicular to the central axis.
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