What is the function of a double-headed bolt? Why choose a double-headed bolt?

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Stud, also known as a double-headed screw or double-headed bolt. It serves as a fixing linkage for connecting machinery; the bolt has threads on both ends, and there is a shank in the middle, which can be either thick or thin. It is generally used in mining machinery, bridges, automobiles, motorcycles, boiler steel structures, cranes, long-span steel structures, and large buildings, etc. 01 Basic Introduction: A bolt refers to a screw with a relatively larger diameter; it may also lack a head, such as in the case of double-headed bolts. Generally, it is not called a \"double-headed bolt\" but rather a \"double-headed stud\". The most common form of a double-ended stud is one with threads at both ends and a smooth shaft in the middle. Most typical use: anchor bolts, or in situations similar to anchor bolts, for thick connections where ordinary bolts cannot be used. 02 Specification marking: The complete marking for a double-ended bolt with a thread size of d=M12, nominal length of L=80mm, and performance grade of 4.8 is: GB 901 M12×80. 03 Main applications: 1. Used in large-scale equipment where accessories such as sight glasses, mechanical seal seats, and reducer frames need to be installed. This is where double-headed bolts come in handy: one end of the bolt is screwed into the main body, and after the accessory is installed, a nut is attached to the other end. Since the accessory is often removed, its threads can wear out or get damaged; using double-headed bolts makes it very convenient to replace them. 2. Double-headed bolts are used when the thickness of the connection member is very large and the bolt length is extremely long. 3. Used to connect thick plates and in areas where it is not convenient to use hex bolt connections, such as concrete roof trusses, roof beam suspension units, and single-track beam hangers. 04 Purpose of anti-loosening: In practical applications, external loads such as vibration, changes in conditions, and high-temperature creep of materials can lead to a reduction in friction. At certain moments, the normal pressure between the threaded parts disappears, resulting in zero friction, which causes the threaded connection to loosen. If this situation repeats itself, the threaded connection will eventually become loose and fail. Therefore, anti-loosening measures must be taken; otherwise, it will affect normal operation and lead to accidents. 05 Surface Treatment: Double-headed bolts generally require surface treatment. There are many types of surface treatments for bolts; the most commonly used ones include electroplating, blackening, oxidation, phosphating, and non-electrolytic zinc coating. However, electroplated fasteners account for a large proportion in the actual use of fasteners. It is particularly widely used in industries and fields such as automobiles, tractors, home appliances, instruments, aerospace, and communications. However, for threaded fasteners, in addition to having a certain degree of corrosion resistance during use, it is also necessary to ensure the interchangeability of the threads, which can also be referred to as thread fit. To simultaneously meet the dual performance requirements of \"corrosion resistance\" and \"interchangeability\" for threaded fasteners in use, it is highly necessary to establish specific standards for electroplated coatings. The GB/T5267.1-2002 standard is one of the standards in the **\"Surface Treatment of Fasteners\" series; this standard includes: GB/T5267.1-2002 ； GB/T5267.2-2002, two standards. This standard is equivalently adopted from the international standard ISO4042 ； 1999. This standard replaces the GB/T5267-1985 standard. 06 Basic Knowledge and Maintenance: Producing double-headed bolts requires specific equipment and machine processing. The actual manufacturing process is relatively simple, involving the following steps: First, it is necessary to straighten the material using a straightening machine; only after this step can the next one be carried out. In the next step, the straightened and long pieces of material are cut into the lengths required by the customer using a cutting machine, thus completing the second step. The third step involves using a thread rolling machine to create threads on the cut pieces of material. At this point, a standard double-headed bolt has been manufactured. Of course, if other requirements exist, additional steps will be necessary. Generally, a bolt refers to a screw with a relatively larger diameter; according to this definition, a screw has a much smaller diameter compared to a bolt. Double-headed bolts lack heads; they are also sometimes referred to as double-headed studs. A double-headed bolt has threads on both ends, with no threads in the middle; the middle part is a solid shaft. Double-headed bolts are used in large equipment such as reducer frames. In practical use, external loads combined with temperature effects can cause friction to decrease; over time, this leads to the loosening and failure of the threaded connection. Therefore, it is necessary to carry out proper maintenance of the double-headed bolts on a regular basis. Double-headed bolts or foot bolts can develop problems due to prolonged mechanical friction. When such problems occur, it is necessary to remove the engine oil pan and carefully inspect the condition of the engine bearing shells, as well as check whether the gap between them is too large; if it is, they should be replaced promptly. When replacing the double-headed bolts, the rod bolts also need to be replaced. For some large-scale equipment such as nail-making machines, if it is observed during normal operation that the engine does not run stably or if unusual noises are heard, it is necessary to stop the machine immediately for inspection, in order to prevent more serious problems from arising. During each maintenance session, the newly replaced double-headed bolts and other components that have been replaced must be inspected. The inspection should focus on the heads and guiding parts of the double-headed bolts; it is also necessary to carefully check each part of the threads for any cracks or dents. Additionally, the shape of the teeth on the double-headed bolts should be examined to determine if there have been any changes. Check whether there are any abnormalities in the pitch; if such abnormalities exist, it must not be used anymore. A torque wrench should be used when installing the rod cover. It must be tightened in accordance with the specified standards; the torque should neither be too high nor too low. Additionally, care should be taken to choose double-headed bolts and studs from a manufacturer that provides compatible products.