| 摘要 |
<p>An expanding wire nail for fastening baseboards and the like to concrete walls has two aligned shank segments integrally joined by a ligament of cruciform cross-section forming a weakened zone between oblique wedge faces on the adjacent ends of the shank segments. The ligament and the wedge faces are formed by plastic deformation of the shank from opposite sides in a forming die assembly. The forming die assembly has opposed forming punches driven in phase opposition, each forming punch being driven in unison with one of two aligned tip cutting punches.</p> |
