A: Metric Screws B: US Screws C: Inch Screws A: Metric Machine Screws: Metric Ex: M3 x 6 – PPB : M3 Machine Screws, 6mm Length, Cross, Flat Head, Black Plated. Finish Code: Finishing Specifications Head Code: The shape of the head. The shape of the screw head. Cylindrical head. Half head. sinking head. Spherical cylinder head. Pan head. Half round head. Hex Head.
Pre-embedded channels are often used in rail transit. There are usually U-shaped channels and C-shaped channels. There are also various widths of openings on one side. The T-bolts used in their connection are generally non-standard parts, which need to be The actual project needs to be customized, mostly for the overall stamping production, the mold cycle is long, the number of mold openings is large, and the production cost is high. Moreover, when assembling and connecting, it is sometimes found that the size of the originally designed t-bolts does not match, and it is necessary to replace t-bolts of different sizes, then it is necessary to redesign and produce non-standard t-bolts, which slows down the entire equipment. processing cycle. Customized T-bolts are often not wide enough in size range, and only a few can be selected for specific assembly and connection, which is difficult to meet the diverse requirements of the production site for bolts.
Screws are a common type of fastener on the market. It is a type of fastener consisting of a head and a screw. It can be divided into three categories according to its purpose: machine screws, set screws and special purpose screws. Machine screws are mainly used for a fastened connection between a part with a fixed threaded hole and a part with a through hole, without the need for nut matching (this connection form is called screw connection, which is also a detachable connection; it can also be Matching with nuts, it is used for fast connection between two parts with through holes.) Set screws are mainly used to fix the relative position between two parts. Special purpose screws, such as eyebolts, are used for hoisting parts.
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.
Screw model Drive Code: groove on the head, characteristic model Length Code: screw length (mm) A-1: Thread Code: screw model Metric screws directly indicate the screw model with the outer diameter of the screw, such as M3, the outer diameter of the screw is 3.00mm. ; M4 means the outer diameter of the screw is 4.00mm. Metric Thread Size x Pitch: Note: The metric screw is behind the screw model, and sometimes the screw pitch is indicated. Such as M3x0.5, M4x0.70, M5x0.8, M6x1. Standard specification, usually not mentioned. A-2: Length Code: Screw length: For metric screws, the screw length is directly marked in mm. The total length of the screw is marked, only the length below the head is calculated, excluding the head height. But With the exception of flat head screws, the total length of the screw is marked with the head height. A-3: Drive Code/ Head Groove, Features.
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