How do Superbolt tensioners work?
A "Superbolt" or "multi-jackbolt tensioner (MJT)" is a direct replacement for hex nuts, covered nuts, bolts, etc. They spin onto your existing bolt or stud and provide a better way to bolt up your joint.
Superbolt tensioners from the Nord-Lock Group consist of three components:
A hardened washer (3) protects your equipment and provides a hardened, flat surface for the jackbolts to "push" against.
The nut body (2) spins on your existing bolt or stud and seats against the washer hand tight (Superbolt nut bodies are typically round).
The jackbolts (1) thread through the nut body and are used to tighten the joint in pure tension, using ordinary hand tools.
Superbolt tensioners working on a bolted joint:
By tightening the jackbolts (1), a strong thrust (axial) force is generated. This thrust force is directed against a hardened washer. Jackbolts have a small friction diameter and can therefore create a high thrust force with relatively little torque input.
The loads are transferred through the nut body (2) which is positioned on the main thread by hand.
A hardened washer (3) is used to transfer the force while protecting the flange face.
The thrust (axial) force of many jackbolts and the opposite reaction force of the main bolt head create a strong clamping force on the flange (4).
The thrust (axial) force from the jackbolt creates an equally strong reaction force in the main bolt (5).