What does a torque wrench measure?

A torque wrench measures rotational force, which is a crucial aspect of tightening fasteners like nuts and bolts to specified torque levels. This measurement is essential in many mechanical and structural applications where proper tension ensures that components are securely fastened and function correctly under operational loads.

When you apply torque to a bolt using a torque wrench, you are not just applying a linear force; instead, you are exerting a force at a certain distance from the pivot point (the center of the fastener), which produces rotational motion. The torque is calculated as the product of the force and the distance from the pivot point, emphasizing the importance of measuring the combined effect of these two aspects to achieve the desired tension without over-tightening, which could lead to stripping threads or damaging the components involved.

In contrast, measuring the force applied to the nut, the distance from the lever arm, or the linear motion of the bolt does not directly address the torque being generated or the effectiveness of the fastening process, which is why they are not the correct focus of what a torque wrench is designed to measure.