How to Use a Torque Wrench

What is a torque wrench?

A torque wrench is a tool for tightening bolts and nuts. It comes in handy when some parts are hard to reach. 

Applications of Torque Wrench

Torque wrenches are a bit more difficult to use than general wrenches, so it is recommended that users develop a good understanding of how they work. Here, we introduce the main types of torque wrenches and explain their use and precautions for their use.

Torque wrenches are indispensable tools in machine maintenance, automobile maintenance, railroads, construction, plants, and other sites where torque control of bolts and nuts is required. They are used when bolts and nuts need to be tightened at a specified torque value or when multiple bolts and nuts need to be tightened with uniform torque.

How to use a torque wrench?

Using a torque wrench requires a bit of finesse. We will introduce several types of torque wrenches and briefly explain how to use each type.

When using a torque wrench, please carefully check the assembly manual or work instructions for the torque value to be set and follow the prescribed instructions.

Preset type

The pre-set type is a type of torque wrench that is used after the desired torque value has been set on the machine in advance.

After setting the torque value, the wrench is set on the bolt or nut and turned. When the torque reaches the set value, the wrench notifies the user with an audible sound. There are two ways to set the torque value: mechanically or digitally.

Plate type

This is a type of torque wrench in which a pointer attached to the wrench deflects on the scale according to the tightening force, indicating the torque value. The wrench is set to show zero on the scale in the no-load condition before use.

Although simple and straightforward in construction, incorrect use will result in incorrect readings. To become proficient in its use, a little practice is required with a proper understanding of how to apply force, grip position, etc.

Dial type

This type of torque wrench is similar to the plate type and displays the torque value on a dial installed on the handle. As with the plate type, this type of wrench is used with the scale set to zero when no load is applied.

Single function type

This type of torque wrench is used only with a certain set torque value. The set torque value cannot be changed easily, for example, a special tool is required to change the set torque value.

This type of wrench is suitable for mass-production assembly sites where the same work is performed continuously, without the risk of the set torque value changing unnoticed during use.

Precautions when using a torque wrench

When using a torque wrench, several precautions must be taken to obtain reliable measurements. The following is a list of important points to keep in mind when using torque wrenches.

  1. Handle a torque wrench with care
    A torque wrench is a kind of measuring instrument. The measurement mechanism may be distorted by impact, rust, dust, dirt, water, etc., which may result in a measurement that is not accurate. Handle the instrument as carefully as possible and do not neglect inspection and maintenance.

  2. Observe the measuring range
    Use the tool only within its measuring range. Forced use beyond the measurement range will lead to malfunction or damage.

  3. Observe the prescribed usage
    Torque wrenches must be used in the specified manner, such as grip position and direction of application of force, or the measured value may deviate. It is advisable to use torque wrenches after fully understanding how to use them. If possible, receive guidance from an experienced person to help you become proficient in the work.

  4. Observe torque value instructions.
    Always follow the instructions in the work instructions or manual for the torque value to be set.


Torque wrenches are indispensable tools for assembly, maintenance, and other sites that require bolts and nuts to be fastened with accurate torque. In order to obtain correct measurements, it is important to follow the correct method of use.