What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
A screw can be equipped with only one spring washer or only one flat washer, or it can also only be equipped with a two-piece combination of flower teeth. The national standard number of the combination screw is represented by GB9074. The commonly used cross recessed small pan head three combination screw national standard is GB9074.8. This .8 refers to the small pan head. That is, the size of the head of the pan head screw that is often said. Denoted by letters as PM. Professional combination screw manufacturers, the habitual expression method is three-in-one PM. The commonly used cross recessed large pan head combination screw national standard is GB9074.4. Professionally called large pan head combination screws. Or R head, or B head. That is to say, the head of this combination screw is larger and thicker than the head of the small pan head combination screw. There is also a commonly used external hexagon combination screw, which is a cross external hexagon combination screw. It is often called a socket hexagon combination screw. The national label is GB9074.13.
The capped nut can prevent the bolt connection from directly contacting with the outside world, which is corroded and makes it difficult to disassemble later. Nuts with caps in the prior art are mostly of one-piece structure, and the surface is not treated with anti-oxidation, which is easy to be corroded. In addition to the protective effect, the fastening method is the same as that of ordinary nuts, so it is easy to loosen when subjected to severe vibration. .
Traditionally, the pressure rivets on the product are all beaten by hand by workers, resulting in high scrap rate and low efficiency, and this rivet is not a traditional rivet, so it is difficult to locate and requires high pressure. The rivets are thin, and the pressure is too large to cause deformation of the rivets. If the pressure is too small, it cannot be riveted. Without special positioning and tooling, it cannot be riveted on the riveting machine. The quality of the products produced in this way is difficult to guarantee, and the quality levels of the products in the same batch are uneven. Affect delivery time.
Washers (spring) washers, circlips are elastic pads or card lock washers a washer that prevents bolts from loosening. The working principle of lock washers is very simple. It consists of two washers. The outside is a radial relief surface, and the inside is a helical tooth surface. When assembling, the inner helical tooth surfaces are opposite each other, and the outer radial raised surface is engaged with the contact surfaces at both ends. When the connecting piece is vibrated and the bolt tends to loosen, only the inner helical tooth surfaces of the two washers are allowed to face each other. Staggered movement, resulting in lifting tension, so as to achieve 100% locking.
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