Self-tapping screws and countersunk screws are two different types of screws. Self-tapping screws have a sharp top and deep external threads with a large pitch. They are usually installed using specialized power tools, which include drilling, tapping, fixing and clamping in a single operation. Self-tapping screws can be used on soft materials. Through their external threads, they can "tapping, drilling, squeezing, and pressing" corresponding threads in the material to achieve mutual cooperation. Commonly used in the connection of thinner copper sheets such as wood board and gypsum board.
Drill tail screws are suitable for connecting and fixing thinner panels, such as the connection between color steel plates and color steel plates, color steel plates and steel purlins, wall beams, etc. Its penetration capacity usually does not exceed 6mm, and the maximum does not exceed 12mm. Drill tail screws are often used in outdoor environments and have strong corrosion resistance. The silicone sealing ring can ensure that the screw does not leak and has good corrosion resistance.
Self-tapping screws and drill-tail screws are essentially the same type of screws, and they can both be clamped without tapping or using nuts. The difference between them depends on the application environment. For harder materials, the screw is more difficult to penetrate, so the tip shape of the drill screw is more similar to a twist drill, which can penetrate harder materials more easily. For soft materials, self-tapping screws are more commonly used.
In order to ensure the normal operation of the equipment, special screws are inconspicuous small parts of the equipment, and regular maintenance is very important. Due to the importance of special screws, in order to avoid problems, the following aspects need to be paid attention to during maintenance:
Remove debris: Special screws need to be cleaned with silicate and fully washed with water after quenching. To prevent residue and debris, great care must be taken during the washing process.
Avoid damage to special screws: Sometimes special screws will change color after heat treatment, and there may be oily residue after soaking in ether, which indicates that the surface of the special screws is not clean. Analysis found that this may be due to improper stacking of special screws during heating, resulting in slight oxidation in the quenching oil.
Remove surface residue: High-strength screws that are not acid cleaned and adequately rinsed may leave a white residue on the screws. Upon inspection it was found that this may be phosphide.
Note: This excerpt contains some errors and ambiguities in the original text. For detailed and accurate information, please refer to the original text or consult relevant professionals.
