Tek screws, also called self-drilling screws, are self-tapping fasteners that have a drill bit end allowing them to be used for screwing materials such as wood and metal together without pre-drilling. Wings right behind the drill point enlarge the hole in the fastened material, allowing the threads to pass through without contacting the fastened material. This added clearance prevents separation of the fastened material from the base metal (known as “jacking”). Flat Head Screws feature a countersunk head for a final application where the fastener runs flush with the surface.