| 摘要 |
The tool comprises first and second parts mounted for axial movement relative to one another, having portions which can be brought into and out of mutual intercalation by this axial movement. The portions carry projectins which form grooves of opposite hands. When the tool is used to produce a joint outer member by being placed in a hollow bank which is forced through a die to form the material of the blank around the projections, the tool is withdrawn from the formed blank by helically withdrawing one portion, with its projections moving along the grooves formed thereby, followed by helically withdrawing the other portion with its projections moving along the grooves which they have formed. |
