# Bolt Torque

Torque, also called "moment of force", is a rotational moment. It is a measure of how much twisting is applied to tighten (turn) the nut on a bolt. When bolting flanges together or anything else tor that matter, tightening the nut stretches the bolt adding pressure to the gasket. The bolt are designed to stretch a bit acting like a spring. Different factors can affect the torque like number of threads, oil, rust, type of material, etc.

## formula

\(T = \frac {kdp} {12} \)

Where:

\(T\) = torque (ft-lbs)

\(k\) = torque coefficient (dimensionless)

\(d\) = nominal diameter (inches)

\(p\) = desired clamp load tension (lbs)