Contour Enthusiasts Group Archives Forums General Common Interests using an extension on a torque wrench

Originally posted by Rara:

---

Um, guys, if I'm reading the original post correctly, he wasn't talking about extending the length of the handle, but about adding a standard extension between the torque wrench and the socket.

In this case, yes, you will lose some small amount of the applied torque, because some of the torque will go into the twisting of the extension, because it will basically act like a torsion spring. The general rule of thumb I've always followed is keep the distance from the tq wrench to the fastener as short as possible, and when you must use an extension, raise your applied torque a little bit; usually I'll lean toward the higher end of the spec of whatever I'm tightening when that is the case.

---

Brian - this is exactly what I was getting at , when I joined in on the conversation .


This is a dogbone . It's a pretty crude pic , but it does the job .
"A" is the torque wrench
"B" is the dogbone
Where "A" & "B" meet is where the square-drive is on your torque wrench (i.e. - where your socket attatches) .
The hexagon at the left of the dogbone is where you'd hook it to the nut/bolt you wish to torque .

Here is the formula for figuring out the proper torque generated by the dogbone extension :



Using (once again)
A = length of torque wrench
B = lengthe of dogbone adapter
C = torque wrench actual setting
D = desired torque at nut/bolt

There are many ways to make/use a dogbone , but the result is the same - you can torque something far above the limit of your torque wrench by using one . Extending the length of the handle does NOT . Once the torque wrench clicks/beeps , torque is reached , job done .