The use of tension control bolts is most common in the steel structural building frame construction and manufacturing industries. These bolts are uniquely designed to allow tightening to the correct torque or tension without over or under tightening.
This is critical in steel buildings and construction where the weight of the materials can easily create a shear force if not securely attached. As this is very different than wood or light types of sheet metal or other composite materials, the tension control bolts are central to a safe construction project that meets building codes and industry specifications.
The Design
The design of tension control bolts makes them very easy to identify. They come in a range of different lengths and diameters for the different type of construction needs.
The bolt comes with three different parts to the assembly. The bolt, washer, and nut, as well as spline, are all included as one unit. The spline is designed to break at a specific tension, which prevents any further tightening of the nut. This prevents the risk of possibly weakening the bolt through excessive torque.
Each of the bolts will have a specific grade or designation. This allows for easy match up of the correct bolt for the particular construction needs. Lengths typically range from one and a half to up to three and three-quarter inches for standard sizes. Different thread sizes are available based on standard thread designations.
The alternative name for these bolts is twist-off bolts, which really describes just what happens when they are in use. They also required a specific type of electric wrench, more specifically a shear wrench. With an experienced operator, it is possible to very quickly and accurately install these bolts, making them a cost and time-saving choice on large as well as small jobs.
