A special bolt that has a snap-off spline is a:

A special bolt that features a snap-off spline is categorized as a tension control bolt. This type of bolt is specifically designed to ensure that the proper tension is applied during installation, which is critical for achieving the structural integrity of connections in steel structures.

The unique design of tension control bolts includes a spline that breaks off once the correct tension is reached. This allows the user to easily determine when the bolt has been tightened adequately, as the snap-off action provides a clear indication that the installation process is complete. Tension control bolts are highly effective in preventing issues such as under-tightening or over-tightening, which can compromise the strength and safety of the connections.

Other types of bolts, such as hex bolts or structural bolts, do not have this snap-off feature and therefore do not provide the same level of assurance regarding tension application. Socket bolts may also lack the specific characteristics associated with tension control, making them unsuitable for this particular application. This precision in tensioning is why tension control bolts are chosen for critical connections in ironworking and structural applications.