Multiple use screw with tapered threads

A screw, comprising:

• a head having a periphery adapted to engage a driving tool;
• a flange adjacent said head extending beyond said periphery;
• a longitudinally extending shaft attached to said head having a first shaft segment adjacent said head and a second shaft segment adjacent said first shaft segment and distal from said head, said shaft having a first lateral dimension adjacent said head, a second lateral dimension at a distal end portion of said second shaft segment, and a third lateral dimension intermediate said first and second lateral dimensions at a junction of said first and second shaft segments, said first dimension being greater than said second dimension and equal to said third dimension so that said second shaft segment tapers between said second and third lateral dimensions and said first shaft segment does not taper between said first and third lateral dimensions;
• and
• a set of threads on said shaft having a helical pitch of about nine degrees and forming a flank angle of about fifteen degrees relative to a horizontal axis of said shaft, said pitch and said flank angle of said threads remaining constant throughout the length of said threads unchanging between said first segment of said shaft which contains threads for engaging a metal clip nut and said second segment of said shaft which contains threads for engaging a plastic boss.