What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
Materials and main equipment: 1.1 Bolts, nuts and washers shall be accompanied by quality certificates and shall comply with design requirements and national standards. 1.2 The high-strength bolts should be stored in categories according to their specifications, and should be protected from rain and moisture. Do not use if the bolts and nuts are not matched and the threads are damaged. If the bolts, nuts and washers are corroded, the tightening axial force should be sampled and used only after meeting the requirements. Bolts, etc. shall not be contaminated by soil or oil, and shall be kept clean and dry. It must be used in the same batch according to the batch number, and must not be mixed or mixed. 1.3 Main tools: electric torque wrench and controller, manual torque wrench, manual wrench, wire brush, tool bag, etc. 2 Operating conditions: 2.1 Friction surface treatment: The friction surface is treated by sandblasting, grinding wheel grinding and other methods, and the friction coefficient should meet the design requirements (a requirement is that the Q235 steel is above 0.45, and the 16 manganese steel is above 0.55). The friction surface wood is allowed to have residual iron oxide scale. The treated friction surface can generate red rust surface and then install the bolts (generally stored in the open air for about 10d). The sandblasted friction surface can be installed without rusting. When grinding with a grinding wheel, the grinding range is not less than 4 times the diameter of the bolt, the grinding direction is perpendicular to the direction of force, and the friction surface after grinding should be free of obvious unevenness. The friction surface should be prevented from being polluted by oil or paint. If polluted, it should be cleaned thoroughly. 2.2 Check the hole size of the bolt hole, the burrs on the edge of the hole must be removed. 2.3 The bolts, nuts and washers of the same batch number and specification should be packaged for use. 2.4 Electric wrenches and manual wrenches should be calibrated.
The main purpose is to make industrial products form a fixed one. In use, it often occurs that the teeth cannot be closely attached, and the screw heads are broken if they are locked too hard, or the teeth are not locked tightly and fail to meet the conditions of use, all of which are accuracy problems. . Screws are mass products, not hand-made works of art. In mass production, they are supplied to consumers in order to achieve high precision, stable quality and popular prices. The accuracy of screws is usually 6g (class 2, the American standard IFI is 2A teeth), and the rough screws used in construction projects are 8g (class 3, IFI is 1A teeth). Common types of screws Screw A: Machine Screw: Machine screw B: Tapping Screw: Self-tapping screw (for metal and plastic) B-1: Sheet Metal Tapping Screw. (Iron die self-tapping screw) B- 2: Plastic Tapping Screw. (for plastic, self-tapping screw) C: Wooden Screw : Woodworking screw D: Drywall Screw : Cement wall screw E: Self Drilling Screws (stainless steel drilling screw, composite material drilling screw) F : Expansion screw, four-piece expansion screw, also known as: four-piece gecko. The grades of expansion bolts are divided into: 45, 50, 60, 70, 80. Materials of expansion screws: mainly austenitic A1, A2, A4, 1 stainless steel plate, metal steel plate, galvanized steel plate, engineering installation. 2. Indoor and outdoor installation of metal curtain wall and metal light compartment. 3 Generally, angle steel, channel steel, iron plate and other metal materials are combined for installation. 4. Assembly engineering of car boxes, container boxes, shipbuilding, refrigeration, screw machine equipment, etc. Features: 1. Drilling and tapping, locking is completed at one time, and the bonding force is strong. 2. Save construction time and improve work efficiency. E-1:STAINLESS STEEL SELF DRILLING SCREWS E-2:Bi-Metal Self Drilling Screws Common materials of composite drilling screws a.Low Carbon Steel: carbon steel carbon steel is divided into low carbon steel, medium carbon steel, high Carbon steel and alloy steel. b. SS-304: Stainless Steel 304 and 316 belong to stainless steel c. SS-302: Stainless Steel 302: better structural toughness d. Aluminum 5052: Aluminum alloy 5052 d. Brass: Brass e. Bronze: Bronze f . UNS C11000 Copper: Antimony Copper
Fasteners such as bolts and rivets are called the rice of industry, and they are used in infrastructure construction, equipment machinery, automobile manufacturing, electronic information, aerospace and other industries. According to the mechanical properties of fasteners, fasteners are divided into high-strength fasteners and ordinary fasteners. At the end of the 20th century and the beginning of the 21st century, with the rapid development of the economy, the demand for anti-seismic and anti-loose fasteners surged. Although the fasteners are small, their quality and reliability play an important role in the performance and structural safety of the main engine. Incredible.
However, although the above-mentioned screw belt (2) can achieve the expected effect, it is also found in its actual implementation. Although this structure has multiple grooves on both sides of the main body for the driving and turning of the locking screw tool, However, the groove is only used for driving the screw belt drive, and since the screw will swing on the screw belt, it is impossible to stably align the screw on the screw belt with the point where the screw is to be set. , which leads to great inconvenience in operation and use, and also affects the efficiency of screw and screw installation, so that there is still room for improvement in the overall structural composition.
The above content is uploaded by Yueluo or the Internet. If there is any copyright issue, please contact [email protected].
