Patent ID: 7681297

Claim:
A method for forming a seam for ductwork having a male end portion integrally formed at a distal end of a duct wall, said method comprising the steps of: integrally forming a female end portion at another distal end of said duct wall; integrally forming said female end portion includes bending a first fold beginning at a break point of said duct wall to extend at a hemmed angle towards an interior of said ductwork and bending a second fold back upon said first fold to extend substantially adjacent to said break point forming a hemmed ridge interior of said ductwork bending a third fold beginning substantially adjacent said break point and extending substantially parallel to said duct wall, and bending a fourth fold back adjacent said third fold defining a female groove for accommodating said male end portion therein; integrally forming a sealing fold at a distal end of said fourth fold; and bending said sealing fold transverse to said female groove prior to said male portion being inserted into said female groove.