What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
Existing wood screws are composed of a threaded portion with a tapered angle and arranged along a tapered stem and a screw head. The head of the screw can be a countersunk head, hemispherical, or other shapes, and the head of the screw has a groove that fits with the tool, a word groove, and a concave cross groove. The taper angle of existing wood screws is either 45 degrees or 60 degrees, and the front end of the taper angle is a pointed point formed by a rotating thread. The existing wood screws have the following three deficiencies in use. Because the taper angle is 45 degrees or 60 degrees, and the thread angle is 64 degrees, the resistance when entering the material is relatively large, so the existing wood screws are manually screwed. It is difficult to screw in, especially when it is used for hardwood materials, and it often happens that the groove of the screw head is screwed out; A large lateral moment will be formed when the screw is screwed, which is prone to the problem of deviation from the position; in addition, because the existing screw is tapered, it will be subjected to both radial force and axial force when entering the material, and its stress state It is more complicated, so it is easy to cause the cracked wood material to burst, and even cause the material to have longitudinal cracks and be unusable.
The gasket side of the above-mentioned nut assembly is in contact with the mounting surface. When the nut is tightened, the gasket squeezes the outer cone surface to make it shrink, and the cone tip faces the same direction as the nut, thereby preventing the nut from tightening, so that the nut fixing effect is not good, and at the same time When multiple nuts need to be superimposed and fixed, two adjacent nuts cannot interact with each other, resulting in poor fixing effect.
Hexagon nuts are usually used in conjunction with bolts and screws to connect and fasten parts. In daily life, ordinary hexagon nuts are sometimes welded to metal plates for use. In the process of welding hexagon nuts to metal plates In order to ensure that the center line of the inner thread of the hexagonal nut is perpendicular to the metal plate, it is necessary to press the end face of the hexagonal nut on the metal plate before welding. Part of the melt is melted. Since the weld is close to the inner thread of the hexagonal nut, the inner thread is often deformed, which affects the fit of the hexagonal nut and the bolt.
A rivet is a nail-shaped object with a cap on one end: in riveting, the parts being riveted are joined by their own deformation or by interference. There are many types of rivets, and they are informal. However, the two ends of conventional rivets are concentric, which is not suitable for special occasions.
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