Types of torque wrenches

Every day, sometimes without realizing it, we apply force to perform our jobs and activities; from something as simple and routine as opening a door to something more "complicated" when we carry our belongings, push something, or perform specific movements. Among these specific movements, there is one in particular where a body rotates around an axis. The property of applying this type of force is known as moment of force or torque.

For example, when pushing a revolving door, using a wrench, pedaling a bicycle, or driving, we can see this phenomenon occur.

A torque wrench, also known as a dynamometric wrench, is a tool that helps us apply this type of force, specifically to screws or nuts that require very precise amounts of force to secure whatever we want to fasten. There are various types, and we can see them in Figure 1.

Something very interesting about torque is that it depends on the distance, which goes from the axis (where we need to apply force) to our position, and the longer that distance, the less force we will need to apply to tighten the nut.

Additionally, torque wrenches have different drive sizes, also known as socket heads or adapters. The basic sizes are as follows:

¼” Drive: Used for small screws and nuts that require a small amount of torque, such as in junction boxes, cabinets, and even motorcycles.

3/8” Drive: For screws and nuts found in differentials, cars, and vans.

½” Drive: This type of socket can be used in cylinders, engine adjustments, trucks, and industrial equipment.

1” Drive: This type of adapter is only required for more robust applications, such as in naval or aeronautical industries.

To choose the correct torque wrench, we must consider the required torque range, the drive size, the environment in which we will use it to know if it will be possible to see the dial; hear the "click" of the click-type torque wrench, etc., the unit system; will we need to measure torque in Newton-meters or foot-pounds?

Since a torque wrench is a precision tool, it must be calibrated to maintain its properties. Table 1 provides calibration recommendations.