Sheet metal joining apparatus

An apparatus for joining two adjacent sheet metal pieces comprising a female die having a central anvil member provided with a working face and support members adjacent said anvil member, each support member projecting beyond a working surface of said anvil member and having cutting edges at the ends of said projections, said support members being adapted to flex away from said anvil member, and a male die having a working surface opposite said anvil working face, said male die working surface having width dimensions less than the distance at which said support member cutting edges are spaced apart, said male die being adapted to be moved and pressed toward said anvil working face whereby when two adjacent sheet metal pieces are positioned between said male and female dies and said male die is moved and pressed toward said anvil working face, the first sheet metal piece, adjacent said male die, is deformed but not cut and the second sheet metal piece, adjacent said anvil working face, is deformed and cut by said cutting edges, the deformation of said first sheet causing a swagging of the material thereof beyond the cut portions of said second sheet so as to join the two sheet metal pieces.