What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
Screws can be divided into machine screws, self-tapping screws, drill-tail screws, wallboard screws, fiberboard screws, wood screws, hexagonal wood screws, non-prolapse screws, combination screws, miniature screws, furniture screws, and electronic screws. Divided into 1. Hexagon head (hexagon head) 2. Hexagon head with flange (hexagon head with flange) 3. Square head (square head) 4. T head (hammer head) 5. Oblate head mushroom head ( truss head) 6. cylindrical head (cheese head) 7. round head (round head) 8. pan head (pan head) 9. countersunk head (flat head) 10. raised countersunk head (oval according to the groove type) Can be divided into 1. Philip 2. Ten / one word 3. One word 4. Inner triangle 5. Inner corner square 6. Cross 7. Rice word 8. Flower shape 9. Plum shape 10. Flower shape one word 11. Special shape 12. Inside Hexagon
Most of the electroplating used for rivet nuts on the market is environmental protection blue zinc, because the salt spray test time of environmental protection blue zinc can reach 72 hours, that is, three days. This kind of electroplating has a longer salt spray resistance time. In fact, for example, for electroplating white nickel, the salt spray time of white nickel is relatively short, and it usually rusts in a few hours, which is less than 10 hours. However, some can be oiled for electroplating white nickel, and the salt spray time of the rivet nut after oiling can be longer. S series rivet nuts are made of free-cutting iron, which is treated after heat treatment. CLS series rivet nuts are made of easy-to-cut stainless steel. The hardness of low-carbon steel plates without surface treatment must be less than 70RB, and the hardness of stainless steel plates must be less than 80RB.
In the prior art, the beams used for installing the curtain wall are mainly divided into two types: closed-cavity structure and open structure, and angle aluminum connection is mainly used for the connection between the beam and the column. As far as the beam of the closed-cavity structure is concerned, after the angle aluminum is used to connect, there are open bolts on both ends of the upper surface of the beam, and the aesthetic performance is extremely poor. As far as the beam of the open structure is concerned, in the actual connection, first fix one corner of the angle aluminum to the beam, and then connect the other corner of the angle aluminum to the column; due to the limited operating space in the beam of the open structure, the angle aluminum is not It is easy and accurate to install, and it takes a lot of time to install; and when the curtain wall panel is heavy, the beam will be twisted, causing the gusset of the opening part of the beam to fall. In addition, due to the limitation of the opening structure itself (an additional gusset or clasp), the aluminum content of the beam is relatively heavy, and the manufacturing cost is high.
The core rivet is another type of single-sided riveting. When riveting, the head of the rivet is hit with a hammer to expose the core, so that it is flush with the end face of the nail head, that is, the riveting operation is completed, which is very convenient, especially suitable for inconvenient Riveting occasions using ordinary rivets (which must be riveted from both sides) or blind rivets (lack of a rivet gun). Usually use flat head rivets, countersunk head rivets are suitable for occasions where smooth riveting is required on the surface. Some rivets can also be matched with clothing, becoming a popular element today, mostly the representative of punk style. In addition, there are paired rivets, which are special. Divided into two parts, the thicker section of the rod with a cap has a hole in the center, and the other section of the rod with a cap is an interference fit. When riveting, drive the thin rod into the thick rod.
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