What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
Hex cap screw and Hex bolt Hex bolt As the name suggests, it is a male threaded fastener with a hexagonal head, designed to be turned with a wrench. According to the ASME B18.2.1 standard, the head height and shank length tolerance of the hexagon head screw (Hex cap screw) is smaller than that of the general large hexagon bolt (Hex bolt), so ASME B18.2.1 hexagon screw is suitable for installation in all hexagon bolts that can be used. places, also including places where the large hex bolts are too large to be used. The screw head of the hexagon socket screw is round on the outside, and the middle is a concave hexagon, and the hexagon screw is the kind of common hexagonal screw head. The hexagon socket head screwdriver looks like a '7'. Cut two sections of a hexagonal steel bar and bend it at 90 degrees to form a hexagon socket head screw wrench, which is sold in hardware tool stores. Hexagon socket screwdrivers are not so-called mobile phone special screwdrivers. Mobile phone special screwdrivers can be bought at the booths that sell repair tools in the electronics market. Hexagon socket head cap screws are often used in machinery, mainly because they are easy to fasten, disassemble, and not easy to slip. The Allen wrench is generally a 90° bend. One end of the bend is long and one side is short. When using the short side to drive screws, holding the long side can save a lot of force and tighten the screws better. The long end has a round head (a hexagonal cylinder is similar to a sphere) and a flat head. The round head can be easily slanted and disassembled, and some parts that are inconvenient to lower the wrench can be installed. The manufacturing cost of the outer hexagon is much lower than that of the inner hexagon. Its advantages are that the screw head (the force position of the wrench) is thinner than the inner hexagon, and some places cannot be replaced by the inner hexagon. In addition, machines with low cost, low power strength and low precision requirements use much less hexagon socket screws than external hexagon screws. [1] Socket cap screw, also known as socket head screw or Allen bolt, is a screw with a hexagonal inner hole on the head, with a hexagonal ruler (hex key, Allen wrench or Allen key) Tighten or loosen only after inserting into the inner hole. The most commonly used hexagon socket head screws are cylindrical head screws with a head diameter of about 1.5 times the main diameter of the thread (1960 series). Countersunk head cap screw. The countersunk hole design allows the screw head to be rotated without being exposed on the surface of the fixed object, so it is mostly used in places where the surface is small and it is inconvenient for traditional wrenches to use.
Pull rivets, * marked as blind rivets, are based on the principle of Hooke's law. After the two joints are clamped with special equipment for pull rivets, the metal of the ring-shaped collar is squeezed and filled to the point where there are many rivets. In the groove of the bolt column of the annular groove, a fastening method that tightly combines the collar and the bolt column. A riveting machine is a mechanical device that uses rivets to riveted items together in batches. The riveting machine is mainly assembled by rotation and pressure. The riveting machine is mainly used in the occasions where rivet riveting is required. The common specifications and models include pneumatic, hydraulic and electric, single-head and double-head.
Bolts made of high-strength steel, or bolts that require a large pre-tightening force, can be called high-strength bolts. High-strength bolts are mostly used for the connection of bridges, rails, high-voltage and ultra-high-voltage equipment. The fracture of this kind of bolt is mostly brittle fracture. High-strength bolts applied to ultra-high pressure equipment need to be prestressed to ensure the sealing of the container.
rotating rod is rotatably installed on one side of the two pillars that are close to each other, and a second bevel gear is welded on the ends of the two rotating rods that are close to each other. The two second bevel gears are meshed with the two first bevel gears respectively. , The first sprocket is welded on the two rotating rods, the chain is meshed on the two first sprockets, and the screw rods are installed on the sides of the two pillars that are close to each other. Above the rod, the second sprockets are welded on the two screw rods, the two second sprockets are connected to the two first sprockets through two chains respectively, and threaded blocks are threaded on the two screw rods. The sides of the two threaded blocks close to each other are symmetrically welded with connecting columns, and the sides of the four connecting columns close to each other are welded with movable rods respectively. The other ends of the support plates are respectively rotatably installed with the same support plate, and the assembly device body is fixedly installed on the top of the support plate.
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