Is there a formula for determining the change in torque reading when using an extension on a torque wrench? Some things need to be torqued properly, but are impossible to reach without an extension, like the oil squirters in a block. If I use a 4-6" extension, how much higher should I set the torque?

 

There is a formula for when you change the actual length of the torque wrench. However if you add an extension vertically to it the torque shouldn't change or at least it shouldn't change enough to matter.

 

For low torque applications the torque wont be affected enough because there will not be enough twisting force to twist the extension.

If you do feel the extension twisting go bigger. It takes some juce (like 100+ftlbs)to noticabley twist or distort a 6" 1/2" drive extensions.