Self-tapping screws are used in both industrial and household daily maintenance applications. Among them, there is a kind of self-tapping screw with triangular teeth, we don't see much, it is mainly used in the plastic injection industry. So what is the difference between it and ordinary self-tapping screws?
1. The diameter of the triangular self-tapping screw is different from the ordinary self-tapping screw. Let me give you a simple example. If we say an ST3.9 self-tapping screw, this 3.9mm size does not mean The top to bottom is so thick, but the thread tip should be thin, and the upper part of the middle will only reach 3.9mm. The triangular thread tapping screw is different. If we say a 3mm triangular thread tapping screw, it means that its entire thread size is 3mm, which will not be thin and then thick like ordinary self-tapping screws.
2. The pitch and the number of threads are also very different. The pitch of the self-tapping screws we use looks at the water chestnut, high and low, and the thread of the triangular tooth looks close to the machine thread, and its thread coil standard is also normal. Self-tapping screws are not the same structure. Its three sides are irregular, and it is not like ordinary self-tapping screws, which can be clicked in any direction, and the size is the same. The thread of the triangular thread tapping screw is triangular, so the position of the caliper is different, and the size is also different.
3. The surface hardness of the two is also different. Generally speaking, the surface of the ordinary self-tapping screw is carburized and hardened, and its surface hardness is higher than that of the triangular tooth self-tapping screw. The average hardness of triangular teeth tapping screws is higher than that of ordinary tapping screws.
4. The applications are also different. Ordinary self-tapping screws are usually used on thin metal sheet metal, which are used to connect two different sheet metal parts. Triangular self-tapping screws are mainly used in plastic parts. For example, some of our TV sets are locked with triangular self-tapping screws for installation. Normal self-tapping screws will produce some iron filings during the installation process. Thread tapping screws will not produce iron filings during installation.