So, you're saying that the two links I posted are erroneous? Bear in mind that the initial question didn't state whether the extension was on the handle end or an adapter forward of the break-over point on the torque wrench. Here's the original question:



so I posted these formulae that deal with FORWARD extensions:

http://www.mdmetric.com/tech/data1torque.html
http://www.specialpatrolgroup.co.uk/spooky/torque/torque.html

Again from memory, I think the discussion was subsequently clarified to specifically ask about the handle end. Meanwhile the Ratio of Circumferences generated some measure of curiousity to me as it is used to figure mechanical advantage.

After reading your post I'm guilty of not going back to actually check if the formulae I posted ALSO included extensions on the handle end, so excuuuse me. From memory I thought the material covered both.

As for your formula, thanks for providing it and the explanation. That's appears to be the correct method of determining torque settings in the situation described. However, it still doesn't answer the question I posed as to the baseline point of mechanical advantage.... that method becomes moot given the formula you put forth, but it's still an interesting question and one I'd like to find the answer to before I die.

IOW, reducing the handle length in your formula by half yields 500 ft/lbs.... by 3/4 yields 250 ft/lbs, and so forth until you finally reach the threads. You can use the Ratio of Circumferences to also find mechanical advantage by the relationship between them, but at some point the initial calculation has to be made. My question is where is the baseline circumference for that calculation set? It can't be the bolt center, because being -0-, all subsequent results would yield -0-.... not an argument of how to determine torque... I think that was abandoned long ago in this thread..... but now you've answered it...

Thanks very much....

Frank