Adjust torque setting when using an extension with a torque wrench?

Extensions and torque wrenches

If you’ve searched the internet to learn whether you have to adjust torque setting when using an extension with a torque wrench, you’ve probably seen conflicting answers. That’s because there are different definitions of the word extension.

Why some extension affect torque setting and other don’t

In this image we see a ½” click-style torque wrench fitted with a 6” long ½” drive extension. When a torque wrench is used with this type of extension, you don’t have to adjust the torque setting on the torque wrench. The reason this application requires no adjustment is because the 6” extension is mounted in the centerline of the ratchet head, so the leverage doesn’t change.

In this application, you do not have to adjust the torque setting when using this extension

However, in this image we see a torque wrench with a different type of extension. In this application you do have to adjust your torque wrench because the centerline of the fastener is no longer in the centerline of the torque wrench head. Thus, the leverage is different.

This type of extension requires an adjustment to the torque wrench

When to adjust torque wrench settings when using an extension

Torque wrench and extension formula

Posted on September 5, 2023 by Rick Muscoplat