How to use a torque wrench to tighten hexagonal nuts?

1. Choose a suitable torque wrench: Choose a torque wrench with a suitable range and accuracy according to the specifications of the hexagonal nut, the required torque size, and the working environment. The range of the torque wrench should cover the required torque value, and the accuracy should meet the working requirements.
2. Check the torque wrench: Before use, check whether the appearance of the torque wrench is damaged, whether the scale is clear and readable, and whether the wrench functions normally. Make sure that the torque wrench has been calibrated and is within the calibration validity period. If the torque wrench has not been used for a long time or has been subjected to a large impact, it may need to be recalibrated.
3. Cleaning and preparation: Clean the surface of the hexagonal nut and the bolt that matches it, remove oil, impurities, rust, etc. to ensure good contact and torque transmission. At the same time, clean the head and sleeve of the torque wrench to prevent debris from affecting the tightening effect. If necessary, apply an appropriate amount of lubricant to the threads of the nuts and bolts, but be careful to choose a suitable lubricant to avoid adverse effects on the connecting parts.
4. Install the socket (if necessary): If the torque wrench does not fit the hexagonal nut directly, you need to select a socket of the appropriate size and install it on the head of the torque wrench. Make sure the socket matches the hexagonal shape of the nut exactly and fits securely on the nut to prevent slipping or falling off during tightening.
5. Set the torque value: Determine the required torque value based on the specifications and connection requirements of the hexagonal nut. You can refer to relevant technical standards, equipment manuals, or engineering drawings to obtain the accurate torque value. Then, follow the operating instructions of the torque wrench to adjust the torque setting of the torque wrench to the required value. Some torque wrenches have a digital display or dial that allows you to read and set the torque value directly; while other types of torque wrenches may require you to set the torque by turning an adjustment knob or using other specific methods.
6. Hold the torque wrench correctly: Hold the torque wrench with both hands, making sure your hand position is comfortable and stable, and you can apply even force. Generally, one hand holds the handle of the wrench, and the other hand can help stabilize the wrench or provide additional support. Avoid operating the torque wrench with only one hand to avoid uneven torque application or the wrench falling out of your hand.
7. Align the nut and pre-tighten: Align the head or sleeve of the torque wrench with the hexagonal nut to ensure that the two fit perfectly. Before starting to tighten, gently rotate the nut by hand to make it initially engage with the bolt to achieve the pre-tightening effect. This helps to reduce the initial friction when tightening with a torque wrench and ensure that the nut can enter the tightening position correctly.
8. Apply torque slowly: Start to rotate the handle of the torque wrench slowly to gradually apply torque. During the tightening process, keep the axis of the torque wrench coincident with the axis of the nut to avoid skew or distortion to ensure that the torque can be accurately transmitted to the nut. At the same time, pay attention to the reading or indication of the torque wrench to ensure that the applied torque does not exceed the set torque value.
9. Operation after reaching the torque value: When the reading of the torque wrench reaches or approaches the set torque value, rotate the handle more slowly to accurately control the application of torque. Once the torque reaches the set value, the torque wrench usually makes a "click" sound or provides other obvious indications that the required tightening torque has been reached. At this time, stop rotating the handle immediately to avoid over-tightening the nut.
10. Check the tightening effect: After tightening the nut, check whether the nut is firmly fixed on the bolt and there is no sign of looseness or rotation. You can gently shake the connection parts by hand to check for abnormal looseness or noise. In addition, other tools (such as torque testers) can be used to spot check the tightened nuts to ensure that the torque value meets the requirements.
11. Record the torque value (if necessary): In some cases, it may be necessary to record the tightening torque value of each hexagonal nut for quality control and traceability. The torque value can be recorded in the corresponding form, report or equipment maintenance record, including information such as the specification, position, tightening date, etc. of the nut.
12. Disassemble the torque wrench (if no longer in use): If all nut tightening work is completed and the torque wrench is no longer needed, it can be disassembled or adjusted to a loose state according to the operating instructions of the torque wrench, and the torque wrench should be properly stored to avoid damage or loss.