Q. What is an HSFG bolt?

Bolts with high final tension strength are called high strength final tension (HSFG) bolts. The tension in the bolt prevents the contact between the plies steel parts in a joint from sliding with respect to one another preventing any relative motion between them. As their name implies HSFGs are grips that rely on friction to achieve a stronghold. In contrast to the shear stress that keeps plates together in a conventional bolt which is borne by the bolt shank the clamping force of an HSFG prevents the plates from moving apart.