How Do Piano Tuning Wrenches Influence Flagpooling and Fulcrum Dynamics?

[corfelga]

Hello everybody,

I have some interest in physics and I am an amateur piano tuner.

So I was reading the piano tuners forum and I stumbled upon this thread:

http://www.pianoworld.com/forum/ubbthreads.php/topics/616245/1.html

The discussion is about piano tuning wrenches and how the wrench affects flagpooling of the pin.

You can get a rough idea of the wrench and pin from here:

http://www.paulhahn.com/images/piano_tuning.jpg

He is saying the you can view the tip that attaches to the pin as a t-wrench and the handle is turning the tip wrench and depending on where it attaches to the pin it changes how the pin flagpools. He has drawings and explanations in the thread.

Where is the fulcrum in a turning situation? If I put a wrench on a bolt, on which contact side is the fulcrum? Does the shape of the wrench matter or is the distance from the point of force application to the turning point all that matters?

The idea that the tip of the head changes the forces applied to the pin doesn't seem correct, but I can't explain why. I would appreciate if you could shine some light on it.

 

[Drakkith]

Hrmm. I'm not sure, but I think it might be right in the middle of whatever you are turning.