A preset break-over torque wrench limits the amount torque applied to a fastener and improves the control of the bolting process by reducing the risk of both over and under tightening. Upon reaching the preset torque value, the tool “breaks” at a specific point along the tool’s shaft – usually at a pivot point near the tool’s head. The unique break-over mechanism, provides an operator ample time to react once the target torque is reached and to stop applying any additional force to the fastener.
The preset wrench does not feature an external adjustment scale. These tools have an internal torque adjustment mechanism that must be preset using a torque tester. When purchasing a preset break-over wrench, there are two options for setting the torque. For a small fee, the Mountz calibration lab will preset the wrench at the requested torque setting. The tool is delivered with a calibration label and ISO 17025 certificate. The second option is to preset the torque value for the wrench yourself. The video below will demonstrate and provide a general guideline to perform this process.
For measuring torque you will need a torque analyzer system, a hex key set, a wrench head and optional adapters may be needed as well. Always select a torque tester that covers the torque range of the break-over wrench.
Adjusting the Torque Setting for Break-Over Wrench
- Connect the wrench to the testing device and use appropriate adapters if needed.
- Check the current setting of the wrench. Apply torque clockwise slowly until the wrench breaks over.
- To adjust torque setting remove the end cap.
- To increase the torque setting, insert the hex key into the internal adjuster and turn clockwise.
- To decrease the setting, rotate counterclockwise below your desired setting. Then turn clockwise to increase torque to the desired value.
- Do not adjust settings above or below the recommended torque range of a tool.
- Check the wrench and continue adjusting until the desired torque is reached.
- Once the setting seems consistent, then record the final torque readings.
- Apply calibration label and seal.
To maintain consistent accuracy the wrench must be checked periodically. Overtime a torque wrench starts to drift out of tolerance and needs to be calibrated. A suitable calibration frequency depends on usage, application, risk tolerance, performance history and other factors. To minimize any production downtime, a good preventative maintenance plan should include having backup tools on-site.
Using a quality torque wrench and torque measurement equipment makes a safer world through accuracy and precision. Controlling torque is essential for companies to ensure their product’s quality, safety and reliability isn’t compromised. The failure of a three-cent fastener that isn’t properly tightened can lead to catastrophic or latent failures. Fasteners that are insufficiently fastened can vibrate loose and excessive torque can strip threaded fasteners.