Key Friction

[Richard Brekne]

Think of the key stick as a simple lever.  You have a fulcrum, and you 
have two lengths on either side going out from there. Then the 
expression d1 X W1 = d2 X W2 explains what weights need to go where to 
balance things.

If a key stick is exactly the same distance from the front to the 
fulcrum as it is from the back to the fulcrum, and its own weight is 
equal on both sides, then placing any weight on the back will balance 
the same weight on the front.

Keysticks are seldom perfect like this... the back half of the key 
weighs generally less then the front half, and the balance pin hole is 
not neccessarilly at the center of the entire length of the key.

Terrys method prebalances the key, so all you need to do is make sure 
that the distance you go away from the fulcrum is identical on either 
side. Measure :)

Cheers
RicB

Alpha88x@aol.com wrote:

> Greetings,
>
>             What if the amount of weight that you put on the front of 
> a key to make it go down, is different from the amount of weight that 
> you need to put on the back of the key to make it go down? Should the 
> keystick need the same amount in both places to be considered balanced??
>
> Julia Gottchall,
> Reading, PA
>
> In a message dated 1/6/2005 3:40:44 PM Eastern Standard Time, 
> terry@farrellpiano.com writes:
>
>> I'm sure Ric will answer with some fancy jig (I think Stanwood has 
>> some such device), but all you really need to do is set some weights 
>> on the key whereever needed so that the key balances - like a 
>> see-saw. The see how much weight needs to be added to the front to 
>> make it go all the way down and the same in the back. You may be 
>> surprised........
>>  
>> Terry Farrell
>>
>
>