Unlike tapping screws, these screws drill a hole and tap a thread in a single operation. All you need to install them is a power driver. For effective fastening, the drilling point must fully penetrate all pieces of material being fastened before the first thread engages. The washer and hex head are formed together as one piece. The underside of the head provides a large flat bearing surface that reduces the likelihood of crushing mating surfaces. When you drive this screw, a flexible black EPDM rubber washer bonded to a metal washer compresses, forming a tight seal. Ideal for metal structures and assemblies. Head height includes compressible washer. Length is measured from under washer. Fully threaded. Zinc-Plated Steel offers good corrosion resistance.
