What are the types of screws

Screws are commonly used fasteners consisting of two parts, the head and the screw. They are mainly used to connect fixed parts, mostly for fastening and facilitating installation and disassembly. As screws are increasingly used in our daily lives, in addition to recognizing their advantages, people are beginning to pay attention to their classification, specifications, and models.
Screw type:
1. Slotted plain screw
Mostly used for connecting smaller parts. It has pan head screws, cylindrical head screws, half countersunk head screws, and countersunk head screws. Pan head screws and cylindrical head screws have high head strength and are attached to common components; The head of a half countersunk head screw is curved, and its top end is slightly exposed after installation, and it is beautiful and smooth. It is generally used in instruments or precision machinery; Countersunk screws are used where the head of the screw is not allowed to be exposed.
2. Hexagon socket and hexagon socket torx screws
The head of this type of screw can be embedded in the component, which can apply greater torque, and has higher connection strength, which can replace hexagon bolts. It is commonly used at joints that require compact structure and smooth appearance.
3. Cross recessed plain screw
It has similar use functions to slotted ordinary screws and can be replaced with each other. However, cross recessed ordinary screws have a higher groove strength, are not easy to screw out, and have a more beautiful appearance. When using, it is necessary to use the matching cross shaped screwdriver for loading and unloading.
4. Eyebolt
The eyebolt is a kind of hardware accessory for bearing weight during installation and transportation. When using, the screw must be screwed into a position where the bearing surface closely fits. It is not allowed to use tools to tighten it, nor is it allowed to have a load perpendicular to the plane of the lifting ring acting on it.
5. Set screw
The set screw is used to fix the relative position of the machine part. Screw the set screw into the screw hole of the part to be tightened, and press its end tightly against the surface of another part, that is, fix the previous part on the latter part. Set screws are usually made of steel or stainless steel, and their end shapes include tapered, concave, flat, cylindrical, and stepped shapes. The end of a set screw with a tapered or concave end directly presses against the part, and is generally used in places where disassembly is not frequent after installation; The flat end set screw has a smooth end and does not damage the surface of the part after tightening. It is used at joints where frequent adjustment of position is required, and can only transmit small loads; The cylindrical end fastening screw part is used to adjust the fixed position frequently. It can withstand large loads, but its anti loosening performance is poor. Therefore, it is necessary to take anti loosening measures when fixing; Stepped set screws are suitable for fixing parts with larger wall thickness.
6. Self tapping screw
When self tapping screws are used on the connected parts, the connected parts may not be pre threaded. Use screws to directly tap out the threads during connection. It is commonly used to connect thin metal plates. There are two types of taper end tapping screws and flat end tapping screws.
7. Self tapping locking screw
Self tapping locking screws not only have a self tapping effect, but also have low screwing torque and high locking performance. Its thread has a triangular cross-section, and the surface of the screw has been hardened to provide high hardness. Its thread specifications range from M2 to M12.