Patent ID: 7513728

Claim:
A fastener comprising: an elongated shank having a reduced taper at one end, said shank having a cross-sectional shape with a predetermined periphery that is bisected by a straight parting line in two spaced locations on said shank periphery, said parting line intersecting no voids within said shank and defining a pair of opposed side portions of said shank, said parting line being defined as a cross-section of a shape when two opposing dies meet in the formation of the shape; said predetermined periphery including at least one spaced fin-like protuberance on each of said opposed side portions protruding at approximately right angles to said parting line, each said protuberance having a substantially straight side on any side facing an adjacent said protuberance on each said side portion of said shank; and a pair of intervening valleys disposed respectively on opposed sides of said at least one protuberance on each said side portion and curved inwardly toward and terminating short of said parting line.