US Patent 9709086 Self-drilling, self-cleaning panel fastener

A self-drilling, self-cleaning fastener for a panel includes a head having a top side and an underside. The head has a diameter. A shank depends from an underside of the head and has a diameter less than the diameter of the head. A knurled region is adjacent the shank. The knurled region has a diameter and a plurality of spiral formed knurls having a twist in a first direction. The knurls define a major circumference as measured around peaks of the knurls. A threaded region is adjacent the knurled region and has a diameter less than the diameter of the knurled region. The threaded region has a thread form having a twist in a second direction opposite the first direction. A driving point is at an end opposite the head.