Self Drilling Screws
Also Known as TEK Screws, Drill Point, Self Drillers and Self Tapping
Self Drilling Screws are used primarily when fastening into steel or other metals, and are typically used to join materials like sheet metal. Self Drilling Screws are identified by the unique point or flute at the end of each screw. Self Drillers are used to save time and effort, because they eliminate the need to drill a pilot hole, tap it, and then install the screw.
Self Drilling Screws are distinguished by the TEK number of the tip. Generally speaking, this number has to do with the length of the drill point at the end of each screw. The most common TEK Screw point is a TEK 3. These are used to drill into thinner metals such as 12 gauge steel, and can pierce 20 to 14 gauge metals. On 14 gauge and below, a TEK 5 point is recommended.
Self Drillers are made of hard metal, usually specifically treated to be harder that the metal that is being drilled into. The most common material used in Self Drilling Screws is 410 Stainless Steel. This grade of stainless will provide the corrosion and rust resistance of standard 18-8 stainless, however it has been heat treated (up to 40 Rockwell C) to ensure that the drill point will successfully pierce the metal being drilled into.