Torque Control and Related Terms

Torque is the force applied to something to make it spin (rotate) in machinery. Torque in relation to fasteners is the resistance faced when installing a fastener. Torque control then is simply controlling the amount of torque placed on a fastener without damaging it by over-tightening.

Prevailing Torque	Measure of a screw or nuts frictional resistance to rotation.
Prevailing “Off” Torque	Highest back-off torque on a torque wrench on the first rotation of a screw or nut upon removal.
Installation Torque	The initial torque amount used to install a fastener before Pre-load.
Breakaway Torque	The minimum torque required to start rotation into a nut (in the case of a bolt) or into a pre-tapped hole (in case of a screw).
Breakloose Torque	Minimal torque required to begin the disassembly of a fastener assembly.
Seating Torque	The torque required to produce pressure onto the installation material causing compression by the fastener.

Torque Wrenches are one of the easiest ways to ensure proper torque is met. Simply set the wrench’s torque and then when the maximum is reached the clutch will slip. This slip means the wrench stops putting any more torque on the fastener and it has reached its optimal torque.