Tighten or loosen? your torque wrench can do both!

In the realm of mechanical repairs, torque wrenches are indispensable tools for applying precise tightening force to bolts and nuts. However, a common question arises: can these wrenches also be employed to loosen stubborn bolts? This article delves into this topic, exploring the capabilities and limitations of torque wrenches when it comes to unbolting.

Understanding Torque Wrenches

Torque wrenches are designed to deliver a specific amount of torque, measured in foot-pounds (ft-lbs) or newton-meters (Nm), when tightening a fastener. They consist of a handle, a ratchet mechanism, and a scale or digital display that indicates the applied torque.

Loosening Bolts with Torque Wrenches

While torque wrenches are primarily intended for tightening, they can also be used to loosen bolts under certain circumstances. However, it’s important to note that this is not their intended purpose, and using them for loosening can potentially damage the wrench or the bolt.

When to Use a Torque Wrench for Loosening

• Broken or Seized Bolts: If a bolt is severely rusted, corroded, or otherwise seized, applying a controlled amount of torque with a wrench can help break it loose.
• Overtightened Bolts: When a bolt has been overtightened beyond its recommended torque, using a torque wrench to gradually loosen it can prevent further damage to the threads or surrounding components.
• Specific Torque Requirements: In rare cases, a manufacturer may specify that a bolt should be loosened to a particular torque value. In such instances, a torque wrench can be used to achieve this precise loosening.

Precautions and Limitations

• Avoid Excessive Force: Torque wrenches are not designed to withstand high levels of loosening force. Applying excessive force can damage the wrench’s internal components or strip the bolt threads.
• Use the Correct Setting: Ensure that the torque wrench is set to the appropriate loosening torque value. Over-loosening can weaken the bolt or cause it to come loose completely.
• Direction of Rotation: Torque wrenches are typically designed to tighten clockwise. When loosening, reverse the direction of rotation to avoid damaging the wrench or bolt.
• Alternative Methods: In most cases, it’s recommended to use alternative methods for loosening bolts, such as penetrating oil, heat, or an impact wrench.

Proper Technique for Loosening Bolts with a Torque Wrench

1. Set the Torque Wrench: Adjust the torque wrench to the desired loosening torque value.
2. Position the Wrench: Place the torque wrench‘s socket over the bolt head and ensure it is securely engaged.
3. Reverse Rotation: Rotate the wrench counterclockwise to loosen the bolt.
4. Monitor Torque: Observe the torque wrench‘s scale or display to ensure that the loosening torque does not exceed the specified value.
5. Use Caution: Apply gentle force and avoid sudden or excessive movements.

Alternatives to Torque Wrenches for Loosening Bolts

• Impact Wrench: Impact wrenches deliver high-impact force to break loose stubborn bolts.
• Penetrating Oil: Lubricating bolts with penetrating oil can help dissolve rust and corrosion, making them easier to loosen.
• Heat: Applying heat to bolts can expand the metal, making them easier to turn.

Takeaways: Weighing the Options

Whether or not to use a torque wrench for loosening bolts is a decision that should be made on a case-by-case basis. While it can be effective in certain situations, it’s important to prioritize safety and use the appropriate technique. For general loosening purposes, alternative methods are generally more suitable.

Frequently Asked Questions

Q1: Can I use a torque wrench to loosen any bolt?
A: No, torque wrenches are not designed for heavy-duty loosening tasks. Use alternative methods for most loosening applications.

Q2: What happens if I over-loosen a bolt with a torque wrench?
A: Over-loosening can weaken the bolt or cause it to come loose completely, potentially compromising the integrity of the assembly.

Q3: Is it safe to use a torque wrench to loosen a seized bolt?
A: Yes, but proceed with caution. Use a penetrating oil and apply gentle force to avoid damaging the wrench or bolt.

Q4: Can I use a torque wrench to loosen a bolt that has been tightened with an impact wrench?
A: Yes, but it’s important to set the torque wrench to a lower value than the impact wrench‘s torque output.

Q5: What is the best alternative to a torque wrench for loosening bolts?
A: Impact wrenches are typically the most effective alternative for loosening stubborn bolts.