What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
In specific implementation, the axial three-dimensional shape of the nut and the screw head is in the shape of a pentagonal frustum, the elastic surface of the screw is parallel to the center line of the bolt, and the upper contour line is arc-shaped; the screw can be full or partial thread; the top of the screw head The shape is round.
Alloy Steel Nuts Hexagon Nuts (GB6170/DIN934, GB6175), Flange Nuts (GB6177/DIN6923) Round Nuts (GB812), Small Round Nuts (GB810), American Square Nuts, American Hex Nuts (NI/MEB18.2.2), Heavy Duty Nuts (Metric, US). Specifications: 5/16-4. Nut Specifications Nut specification table is to unify all kinds of nuts in detail, and use the table to subdivide some specifications of nuts. There are many types of nuts, and there are nuts of different materials. Each type of nut has different specifications, and each type of screw also has its mechanical properties and functions.
When used for the connection and fixation of doors, windows, cabinets, etc. involving hinges, the traditional screw fastening method is usually used, and the screws are directly driven into the screw holes of the connected parts, and the screw end caps are directly exposed, which not only affects the connected parts. Moreover, the end caps of the screws exposed for a long time are easy to rust, and there are burrs in the end processing of the general screws. When used for fastening connections, the end caps of the screws are easy to scratch people, which affects the appearance and is not safe.
The traditional fixture shown in Figure 2 is composed of a hardened support cylinder and a hardened shear bar, and has a simple structure. The cylindrical pin is loaded into the hardened support cylinder, and the shear test is completed by applying an axial load to the hardened shear bar. Since the standard stipulates that the gap between the loading part and the supporting part does not exceed 0.15mm, in order to ensure the matching of the gap during the shear test of the cylindrical pin, the diameter of the cylindrical pin on the cylinder is generally equal to the theoretical cylindrical pin. In practical application, the cylindrical pin is irregular in size after heat treatment. To realize the shear test, the cylindrical pin must be inserted into the hole with the help of external force, which is difficult to install and clamp and takes a long time. If the double-sided shearing is performed, that is If the cylindrical pins need to be installed on both sides, the time is doubled, and the notch of the cylindrical pins cannot be guaranteed to face upwards.
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