| 摘要 |
A method of forming a radially expandable externally grooved tubular fastener from metal, comprising the steps of providing a suitable tubular blank ( 11 ) having a tubular wall ( 12 ) and squeezing the tubular wall between an internal member ( 17 ) with a surface which engages the internal tubular wall face ( 15 ) of the blank and a plurality of external members ( 18 ) provided with suitably shaped surfaces engaging the external tubular wall face ( 16 ) of the blank ( 11 ) thereby to form grooves ( 23 ) on the external tubular wall face ( 15 ) of the blank ( 11 ).
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