A superbolt is a unique and highly specialized type of mechanical fastener that serves as an excellent alternative to traditional hex nuts, bolts, and other threaded fasteners. It is specifically designed for applications that involve larger nuts and bolts, typically those with a diameter greater than 1 inch (25 cm), which demand an extremely high amount of force for proper tightening.

In these cases where large fasteners are required, using a superbolt offers several significant advantages. By distributing the force needed to tighten the large fastener over several smaller bolts, it becomes possible to use simple hand tools instead of relying on cumbersome and potentially dangerous large tools like hydraulic wrenches and sledgehammers. This not only simplifies the installation process but also enhances worker safety.

A superbolt is composed of three main components. Firstly, there is a hardened washer that provides a precisely flat surface against which the smaller bolts can push. This washer is crucial for ensuring even distribution of force and maintaining the integrity of the mechanical joint. Secondly, the round-nut body is threaded onto the bolt and rests against the washer. Finally, a series of smaller bolts known as jackbolts are threaded through the nut body and tightened. When the jackbolts are tightened, they exert pressure on the hardened washer surface, thereby securing the mechanical joint by placing the existing nut or bolt in pure tension.

Superbolts are commonly employed in large-scale equipment applications where very high forces or pressures are involved. For instance, in mechanical presses, large diameter columns are utilized to distribute extremely high working loads. In such cases, superbolts ensure a secure and reliable connection. Another example is steam turbines, which generate very high internal pressure. Metal-to-metal mechanical joints secured with superbolts are essential to contain this pressure without leakage. The force required to properly tighten these fasteners is often so great that without the use of superbolts, large and unwieldy tools that pose significant safety hazards would be necessary.

There is a diverse range of superbolts available in the market to meet a wide variety of applications. Superbolt manufacturers provide detailed guidelines to help customers select the correct size and type of superbolt for a specific set of operating conditions. These guidelines take into account factors such as the type of mechanical connection, operating temperature, working loads, and material considerations. Additionally, superbolts can be custom-designed and fabricated to meet the unique requirements of specific equipment applications.

The use of a superbolt can result in significant time savings compared to other mechanical fastening methods. Since only hand tools are needed, the installation process is quicker and more efficient. Moreover, worker safety is improved as there is no need to handle large and dangerous tools. Another advantage of superbolts is that they generate pure tension force when tightened, which eliminates problems such as seizing and thread galling that can occur with conventional fasteners. However, it should be noted that superbolts are generally more expensive than standard mechanical fasteners. Therefore, for each specific application, the cost-versus-benefit of using superbolts should be carefully evaluated to determine if they are the most appropriate choice.