Lee -

Understood - I spent my undergraduate years in e-school, but never worked a day as an engineer (other than summers between years), so have forgotten much. I think what you're referring to in the example of "nothing moving" is called "net torque".

What I was attempting to determine was not where the resulting net torque was applied (or even how much was applied), but what mechanical advantage would be at a given lever length without benefit of a torque wrench. Obviously there's a difference in MA when one grabs the lever at varying distances, but there also has to be a base-line for mechanical advantage determination and to avoid MA values of infinity there has to be a finite number to work with, doesn't it?

If you put a small diameter nut on a thread and then replace it with a larger diameter nut, mechanical advantage has increased in the ability to apply torque to the fastener. So, it seems that some starting point must be identified in order to calculate the mechanical advantage of one over the other. I can see where the nut rotational diameter would not be the base line - would it be the mean thread diameter since that is the only element that doesn't change?

If you use the mean thread diameter circumference as one element and the diameter of the lever length where force is applied as the second element, would division of the mean thread diameter into the lever rotational diameter not yield a mechanical advantage? If so, it would answer the original question of how much force to apply - at what distance - to the lever to gain a torque value without the use of a torque wrench. If that formula won't work, then the only answer lies in the torque angle tables, I guess.

Man, this is like going back to school.... <img src="/forums/images/graemlins/lol.gif" alt="" />

Frank