1. Assembly torque accuracy level: abbreviated as accuracy level. Classification of torque tightening accuracy for different levels of importance in process documents:

A level accuracy: tolerance range is less than or equal to ± 5%.

B level accuracy: tolerance range greater than ± 5%, less than or equal to ± 10%.

C level accuracy: tolerance range greater than ± 10%.

2. Fixed torque tool: a tightening measuring instrument with a torque measuring mechanism.

Fixed torque tools are divided into three categories based on the power source used: manual, electric, and pneumatic.

According to measurement principles, it can be divided into two types: indicating type and preset type.

3. Prefabricated fixed torque tool: a fixed torque tool that reaches a pre-set torque value during use and sends a prompt or automatically stops working.

4. Target torque value: the ideal torque value in the design. For example, if a certain torque value is 80 ± 5Nm, then its target torque value is 80Nm; For a torque value given as a range, such as a torque value of 80-100Nm, the target torque value is the average of the upper and lower limits of the torque range, i.e. (80+100) ÷ 2=90Nm.