Self-tapping screws for non-metallic or softer metal, no bottom hole and tapping; self-tapping screws are pointed, so as to "self-attack"; ordinary screws are flat head, the same thickness.
Self-tapping screw is said: drilling holes for the hole without tapping, with the screws and the general difference, the head for the sharp, teeth from the relatively large, and no trace of wire like a bit, you can not directly into the tapping , Metal and plastic usually use this method.
It can be in the consolidation of the material, by its own thread, will be solidified "attack - drill, squeeze, pressure" the corresponding thread, so that closely with each other
Self-tapping screw is a screw with a drill bit, through a dedicated power tool construction, drilling, tapping, fixed, locking once completed. Self-tapping screws are mainly used for the connection and fixing of some thin plate pieces, such as the connection of color steel plate and color steel plate, the connection of color steel plate and purlins, wall beam, etc., and its penetrating power is generally not more than 6mm, the maximum does not exceed 12mm. Self-tapping screws are often exposed to the outside, and they have a strong corrosion resistance; the rubber seal can ensure that the screw is not seepage and has good corrosion resistance.
Self-tapping screws are usually described by the screw diameter series, the length of each thread thread length and the length of the screw to describe the three parameters. The diameter of the screw diameter is 10 and 12, the corresponding screw diameter is 4.87mm and 5.43mm respectively. The number of threads per length is 14,16,24 three levels, the more the number of threads per inch, Drilling ability is stronger.
