There's a common misunderstanding that these "self-tapping" screws bore their own hole. Regardless of the gauge or thickness of the metal that they are being used on, the installer must pre-drill a pilot hole for the screws. Once the head of the screw penetrates the pilot hole, it will pull the screw body into the hole, thus securing that location. Please also note that a hammer drill should NOT be used to drive in the screws, nor should an electric drill with the torque on the chuck set higher than 6, as that is too intense and the head of the screw will twist off when being drilled into the metal.