Torque limiting extensions, also commonly known as torque sticks, are extensions for impact guns that limit the torque applied to a fastener.
Impact Gun Downside
One of the downsides to using an impact gun is it is impossible to know exactly how much torque has been applied to a fastener.
We have personally seen lugs nuts both very under torqued or very over torqued when tightened when using impact guns.
There is just no way to know reliably know how much torque you have applied to a fastener when using only an impact gun to tighten it.
Torque Sticks Offer a Solution
Torque limiting extensions (torque sticks) were created to solve this problem.
These torque sticks look like normal impact extensions, but they are designed in a way that limits the torque applied to a fastener when using an air powered impact gun.
It may seem to be magic, but there are some well understood physics behind torque sticks.
How do Torque Sticks Work?
They work by flexing at the target torque level, a physical effect called torsion, which basically means the torque stick starts to twist at the target torque.
Torsion limits the torque applied to the fastener to the rated value of the torque stick.
One thing to note is that these torque limiting extensions can only be used with air powered impact guns.
Torque limiting extensions are not designed to work properly with battery powered or other electric powered impact guns.
What are the Best Torque Sticks?
Here are some of the best torque sticks we have found through our research.
Genius Tools Dr. Torque Extension Set
- 1/2″ Drive
- 10 Extensions
- Torque Range 65-150 ft/lbs
- 4% Accuracy
- Color Coded
- Powder Coated Finish
Astro Torque Limiting Extension Set
- 1/2″ Drive
- 10 Extensions
- Torque Range 65-150 ft/lbs
- Chrome Molydbdenum Construction
- Color Coded
- Matt Finish
- One Year Warranty
Capri Tools Torque Limiting Extension Set
- 1/2″ Drive
- 5 Extensions
- Torque Range 65-140 ft/lbs
- Chrome Molydbdenum Construction
- Color Coded
- Matt Finish
- Lifetime Warranty
Other Frequently Asked Questions
Here are some frequently asked questions we see about torque limiting extensions (torque sticks).
Do Torque Sticks Work?
Yes, torque sticks do work.
They do what they are designed to do, but the normal best practices for getting accurate torque results still apply, such as making sure threads are clean, dry, and in good condition.
It is recommend to check final torque with a regular torque wrench to verify fastener torque.
How do I use Torque Sticks?
Torque sticks attach to your air impact gun between to gun and the socket just like a normal extension.
Most torque sticks will come with specifications on how much air pressure, and the supported impact torque range they support.
For best results your air impact should be within these specifications.
When tightening a fastener with a torque stick you should stop once the impact’s hammer starts going, you will know this when the impact starts making the familiar “knocking” sound.
If you continue to tighten the fastener too long after this you will over tighten it.
Do Torque Sticks Replace a Torque Wrench?
While many people report getting accurate torque results using torque sticks, they are not designed to replace your torque wrench.
Most experts recommend using a torque stick with a rating around 20% less than the fastener target torque to start.
Once you use that torque stick to tighten the fastener, follow up with a regular torque wrench to tighten it to the final target torque value.
Do Torque Sticks Work with Electric Impacts?
No, it is not recommended to use torque sticks with electric impact guns.
They are specifically design to be used with air powered impact tools only.
If used with battery or other electric motor driven impact guns their accuracy with be greatly reduced.
