There are so many kinds of small screws, do you know how many types of threads are commonly used for screw fasteners?

    Every day to do machinery to deal with threads, especially hydropneumatic, long time domestic and foreign, metric, imperial, straight, cone, sealed, unsealed, inner, outer, 55 degrees , 60 degree, trapezoidal thread, rectangular thread, Rd bulb thread, bottle thread, various threads, often messed up, there are so many types of threads, generally do not need to touch so much, so just apply What kind of thread on the screw fastener should always be known.
    Don’t look at a small screw, you can see it everywhere, but there are many types of screws and complex specifications. Especially today, people have higher and higher requirements for product quality and performance. Many manufacturers design their own screws and require screw manufacturers to follow The processing and production of your own drawings have made it more difficult to manufacture screws. Today we will take a look at the screw thread type. Let me show you a few screws first:
    There are two large types of threads, one is mechanical teeth, and the other is self-tapping.
    Screws with cross countersunk head mechanical teeth. Mechanical teeth (also known as machine thread teeth) are generally used to match nuts or internal threads. In the general industry, "M" indicates this thread. For example, the specifications of this screw are generally abbreviated as M5X12. The tail of this thread It is flat, and the threaded rod is straight, without arcs, and is generally used for metal fastening or machine connecting parts.
Self-tapping screws with cross-head and triangular teeth. Triangular teeth self-tapping screws, also known as triangular teeth self-tapping locking screws, or triangular teeth screws, national designation GB6560. It means that the tail of the self-tapping screw is triangular, and the thread is triangular. It belongs to a special kind of self-tapping screws. It is a kind of self-tapping screw. Its thread is a common thread with an arc-shaped triangular cross-section. The thread surface also has a high hardness. Therefore, when connecting, the screw can tap the internal thread in the bottom hole of the connected piece. Thereby forming a connection. This screw is characterized by low screw-in torque and high locking performance. It does not need to be equipped with a nut like a mechanical screw. This is better for customers in terms of cost savings.
    A more typical self-tapping screw-cross countersunk head self-tapping screw, this screw is very common, the thread pitch is relatively large, the tail is sharp, the recognition is relatively high, the industry generally uses "ST" to abbreviate this Self-tapping screws, ST4.2X19.

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