The production of double-ended studs requires specific equipment and machine tools; however, the actual manufacturing process is relatively straightforward, primarily involving the following steps: First, the material must undergo a straightening process, in which a straightening machine is used to correct any distortions in the raw stock. Only after this step is completed can the material proceed to the next stage. The second step involves using a cutting machine to cut the straightened, long lengths of material into the specific lengths required by the customer. This marks the completion of the second process. The third step entails placing the cut lengths onto a thread-rolling machine to roll the threads onto them. At this point, a standard double-ended stud is considered fully processed; naturally, if additional specifications are required, further processing steps would be necessary.
Generally speaking, the term "bolt" refers to a screw-type fastener with a relatively large diameter; conversely, a "screw" is typically understood to be a fastener with a much smaller diameter compared to a bolt. A double-ended stud-sometimes referred to simply as a "stud"-lacks a conventional head. Instead, it features threads at both ends, with a smooth, unthreaded shank section in the middle. Double-ended studs are typically utilized in large-scale machinery and equipment, such as gearbox mounts. In practical applications, external loads-combined with vibrations and temperature fluctuations-can lead to a reduction in frictional force; over time, this can cause the threaded connection to loosen and eventually fail. Therefore, it is essential to perform regular maintenance on double-ended studs. Double-ended studs (or anchor bolts) can develop issues after prolonged exposure to mechanical friction. Should such problems arise, it becomes necessary to remove the engine oil pan to thoroughly inspect the condition of the engine's main bearings. One must check whether the clearance between the bearings has become excessive; if the clearance is found to be too large, the bearings must be replaced immediately. Furthermore, whenever double-ended studs are replaced, the connecting rod bolts should also be replaced simultaneously. For large-scale machinery-such as nail-making machines-if the engine is observed to be running unstably or if unusual noises are detected during normal operation, the machine should be shut down immediately for inspection to prevent the occurrence of more serious mechanical failures.
During every maintenance or repair procedure, both the newly installed double-ended studs and any other newly replaced components must be thoroughly inspected. Particular attention should be paid to the head and guide sections of the double-ended studs. Furthermore, each section of the threading must be rigorously examined for any signs of cracks or dents, and the profile of the threads should be checked to ensure its shape remains unaltered. Finally, the thread pitch should be verified for any irregularities; if any anomalies are detected, the component must be strictly prohibited from further use. When installing the connecting rod cap, a torque wrench must be used. It is imperative to tighten it in strict accordance with the specified standards; the applied torque must be neither excessive nor insufficient. Furthermore, care should be taken to select the corresponding double-ended bolts and studs supplied by the original manufacturer.