Product information: Product name: Hexagon socket screws Material: Iron surface You need to drill a small hole of the right size with an electric drill, screw it into the hole with a hex wrench, then add 2-3mm of wood glue inside the hole (on the side wall). Insert the nut and turn it several times, then apply 2-3mm glue to the thread of the nut, then turn the nut 180 degrees, please fully tighten the nut, then the nut will not will not loosen and will connect firmly Note: Pre-drilled The depth should be as deep as the length of the inserted nut, and the bolt can be turned beyond the depth of any part of the nut d end.