What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
At the beginning of the quality inspection process broadcast, we ordered the cross recessed screw and screw wire material into our production screw industry. For manufacturers in the screw industry, we must first detect the wire diameter of the screw wire and the material of the screw. Generally, the wire diameter of the screw is measured by a caliper and a measuring wire. Diameter size, whether it is the same as the size ordered by yourself. After testing these, it is the testing in the production process, starting from the head of the screw, to determine the size of the head, the opposite side of the head, the diagonal angle, the depth of the cross groove, the tolerance range of the screw, and so on. These are checked with calipers. In the inspection of all aspects when rolling teeth, the main thing is whether the thread can pass the pass and stop gauge, and whether the screw thread can pass the gauge and stop. Next is the electroplating measurement problem. After electroplating, whether it meets the requirements of environmental protection and whether it can pass the time required by the salt spray. Tools include environmental testing machines and salt spray testing machines. In short, in the production and sales process of cross recessed screws, there must be necessary tools to detect the quality of screws. The summary should be summarized as follows: calipers, hardness testers, salt spray machines, environmental testing machines, pass and stop gauges, etc. .
In view of the deficiencies of the prior art, Guangdong Yueluo Hardware Industry Co., Ltd. provides a relatively simple screw that can be manually disassembled. In order to achieve the above purpose, Guangdong Yueluo Hardware Industry Co., Ltd. provides the following technical scheme: a screw that can be disassembled manually, including a stud and a nut, and the axial direction of the screw is provided with a screw extending from the nut to the stud. A groove, a control column that is slidably matched with the groove is arranged in the groove, a through groove is opened on the circumferential side wall of the control column, and a circumferential side wall of the control column is provided with a parallel to the axis of the control column. A limit bar, the side wall of the groove is provided with a limit groove that cooperates with the limit bar, the control column is provided with a accommodating groove, and the accommodating groove is provided with a rotating rod that cooperates with the through groove, so The accommodating groove and the rotating rod are arranged separately. Further, a accommodating groove is opened at the corresponding groove on the nut, a baffle is hinged on the side wall of the accommodating groove, and a torsion spring is provided at the hinged joint between the baffle and the accommodating groove.
A pull rivet, this kind of pull rivet has good installation performance, firm connection and long service life, but the defects are: first, after installation and use, if it is damaged, it cannot be reused; second, it is convenient to disassemble, and it also increases the possibility of theft ,. It is not conducive to safety; 3. There is still the possibility of movement in the circumferential direction of the collar, which will affect the riveting effect.
Common fastening screws include self-tapping screws, fine-pitch drywall screws, traditional wood screws, and fiberboard screws. The following are the characteristics of commonly used screws, everyone should choose them reasonably. Self-tapping screws The correct application of self-tapping screws should be used for the fastening and connection of metal materials with pre-drilled holes. It has the function of automatically tapping out the internal thread on the metal body, and can complete the thread engagement with it to play a tightening role. However, due to its high thread bottom diameter, when it is used in wood products, the cut into the wood will be shallower; and because the thread pitch is small, there is less wood structure between every two threads. Therefore, it is unreliable and unsafe to use self-tapping screws for wood mountings, especially loose wood. Drywall Screws The proper use of fine-pitch drywall screws is for fastening and joining between metal studs and plasterboard. It suffers from similar drawbacks as self-tapping screws when used on wood mountings. Moreover, due to the large diameter of the head of the dry-wall screw, the embedding of the head is poor, and it is easy to cause unevenness between the head of the screw and the surface of the mounting part after installation. Traditional wood screws Before using traditional wood screws, pre-drilling holes are required on the wooden mounting parts, otherwise it is easy to cause wood cracking. In addition, since the traditional wood screws are not heat-treated, the use of electric tools can easily cause the groove shape to be damaged, and manual installation is very laborious. Fiberboard screws are relatively new types of wood screws, suitable for power tool installation. However, due to its relatively simple thread design, it still cannot effectively solve the stubborn problem of easy cracking when used on hardwood, and it does not have any advantages in screwing speed and screwing torque. [2]
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