Self-drilling, self-cleaning panel fastener

A self-drilling, self-cleaning fastener comprising:

• a head having a top side and an underside, the head having diameter;
• a shank depending from an underside of the head, the shank having a diameter less than the diameter of the head;
• a knurled region adjacent the shank, the knurled region having a plurality of spiral formed knurls therein having a twist in a first direction, the knurled region having a major circumference as measured around peaks of the knurls and a major diameter measured across peaks of opposing knurls;
• a threaded region adjacent the knurled region, the threaded region having a major diameter less than the major diameter of the knurled region, the threaded region having a thread formed therein having a twist in a second direction opposite the first direction;
• and
• a driving point at an end opposite the head,
• wherein a transition between the threaded region and the knurled region defines a step formed by a difference between the major diameter of the knurled region and the major diameter of the threaded region, and wherein the fastener is a bi-metal fastener.