Basic knowledge of fastener products

Update:17-06-2019
Summary:

Functional aspects: 1. Screw Torque Requirements: The t […]

Functional aspects:

1. Screw Torque Requirements: The torsion force of the hexagonal screw is relatively larger, the torque of the hexagon socket screw is smaller, and the torque of the cross recess is smaller (so the screws are generally ordinary grade screws).

2. Assembling the hexagonal bolts is usually assembled with an adjustable wrench, a wrench and an open end wrench. The adjustable wrench has low assembly efficiency, but it is very versatile. It is suitable for all kinds of head bolts. The wrench has the highest efficiency, but it is not suitable for some occasions. Only one head of a plum wrench can only be used. Two types of head hex screws; the open end wrench is similar to a Phillips wrench, but it can be used with a long sleeve. The smaller the specification of the hex screw, the higher the angular requirement of the hex bolt, otherwise the head will easily slip when subjected to the (wrench) force. In order to save materials, Wenzhou people invented the hexagonal recess. The hex screw of the pocket is light and light, the thickness of the head is thin, the force is easy to slip, and the head may be screwed off.

3. The hexagon socket head cap screws are assembled with an Allen key. The requirements for the hexagon socket are very high. If the hole is larger, the wrench will slip and a small wrench will not be inserted. The smaller the hex specification, the higher the hole requirements. For some large hexagon socket screws, if the inner hexagon is qualified, the wrench can be assembled normally. For some small hexagon socket screws, such as the inner hexagon of the M2, the wrench is inserted into the force. The hex will slip, so a little one is too big to qualify. Therefore, the hexagonal screws of M2, M2.5, and M3 (especially the tightening products) are easy to slip during the assembly process.

4. The Phillips screw is assembled with a screwdriver. It does not need to use too much force, so the strength is only 4.8. Sometimes there are some screws that require high strength, as long as the carburizing heat treatment can be used.

5. In the product supporting use, we generally recommend that the grade of the screw be one level higher than the nut grade, which is the most economical. For example, the 8.8-class screw is used with the 4-level nut; this way, you only need to change the nut for the next replacement.

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