A torque wrench is one of the most important tools when it comes to automotive maintenance. This is because almost every fastener within a vehicle has a torque specification assigned by the manufacturer. In order to ensure torque accuracy, it is important to calibrate and maintain the instrument on a regular basis.
IMPORTANCE OF CALIBRATION
When it comes time to calibrate your automotive tools, it is in your best interest to make your torque wrench your number one concern. Torque is extremely sensitive in most cases. For example, too much torque could lead to stripped fasteners and broken parts, while too little torque could lead to loose pieces and mechanical failures. The exact amount of torque is needed to ensure a screw or fastener is tightened properly. Proper tightness is critical to ensure overall safety and to prevent mechanical failures. To ensure an accurate amount of torque is applied, a calibrated torque wrench is needed. The only way to be sure a torque wrench is accurate, consistent and repeatable is to periodically validate its performance.
FREQUENCY OF CALIBRATION
A torque wrench’s calibration will begin to drift after frequent use, especially when used within a maximum operating range. Many other factors contribute to calibration drift as well, including:
It is recommended to have a torque wrench calibrated after 2500 to 3000 uses, however, this is just a basic guideline. Logically, the more frequently a torque wrench is used, the more frequently it should be calibrated.
Many individuals fail to store a torque wrench at its lowest marked setting. This is completely necessary for an adjustable torque wrench because of the tension spring. If a torque wrench is stored at its highest setting, then the tension spring will continue to be under load, which in turn weakens the spring over time. This leads to chances of less torque and inaccuracy. If a torque wrench is stored for a long time in this setting, it will need to be re-calibrated before use and in some severe cases replaced.
A torque wrench’s purpose is to be used for applying a specified amount of force to a given part. If a torque wrench is used for any other task, chances of instrument overload are likely, which could lead to inaccuracy and in worse cases, permanent damage. If a torque wrench ever experiences overload, it should be re-calibrated before use. Notably, if a torque wrench is dropped, it should also be re-calibrated before use to ensure precision.
Using a torque wrench during specific weather or temperature conditions could affect the calibration of the torque. For example, if used in below freezing or excessively high temperatures, the risk of the torque wrench developing condensation is high, which in turn could cause rusting. Rusting can also be caused by using a torque wrench during the following weather conditions, rain, sleet, or snow. When a torque wrench develops rust, the accuracy and performance of the instrument could be at risk. If a torque wrench has endured any of the following, it should be sent for re-calibration before use.
Calibration of a torque wrench is of extreme importance. A regular schedule should be made and followed to ensure the overall accuracy and repeatability of the instrument’s measurements. Similarly, a schedule should be created for all automotive tool calibrations. Automotive tool accuracy is crucial for the overall safety and functionality of a vehicle.