Key return speed

[A440A@aol.com]

Vladan writes:

<< I think the most important factor is the rotational

moment of inertia of the key stick.  This is

largely determined by the amount of lead and the position

of the lead in the key.  For fast return, you want less

lead, and the lead should be as close as possible to

the fulcrum point (balance pin).<< 

     The lightest key in the world will not return very fast if the capstan 
is too close to the balance pin. 

 

>>In order to achieve that, and still maintain the proper

static balance weight, the action needs to have a low

ratio geometry.<< 

      Is this to say that the high ratio actions will not repeat as fast?   
My experience is otherwise. 
 
>>The other factor influencing return speed is the strength

of the wippen spring.  This adjustment, like all others,

is a compromise too.  A stiff spring setting will help

return the key faster.<< 

       I have not found this to be so.  All other things being equal( and 
within bounds), there is virtually no measurable difference in repetition speed 
between a spring that throws the hammer off the jack when released from check 
and one that simply lifts the hammer just slowly enough that it can't be felt.  
However, the former makes escapement a clumsy chore for pp playing.  
     I still maintain that the major determinate in repetition speed is the 
height of check. 
Regards,  
Ed Foote RPT 
http://www.uk-piano.org/edfoote/index.html
www.uk-piano.org/edfoote/well_tempered_piano.html