overcentering justified?

[A440A@aol.com]

I wrote:
<< >Repetition speed is usually more dependant on checking distance than 
>anything else. How far away from the string are these new hammers >checking? 

Bob sez:
>>I set the checking distance of the new long bored distance hammer at the 
same  height as the old  hammer and the new did not repeat anything like the old.
     During very fast repetition, does the hammer tail come into contact with 
the backcheck even if the checking distance is set as high as possible (but 
not so high that it drags on the way up), or isn' t the knuckle bouncing off of 
the top of the jack? <<

Are the tails shaped on a 2.5" radius?  and are the back-checks leaning 
slightly away from the  tail at rest?   
    As far as knuckles bouncing off the top of the jack, the jack has to be 
under it to do that, so the knuckle will to either need to lose contact with 
the jack on the way up, or the jack must find time to reset.   
  Was the only thing changed in this action the hammers?  No changes to drop, 
spring or balancier?   
 
Ed Foote RPT 
www.uk-piano.org/edfoote/
www.uk-piano.org/edfoote/well_tempered_piano.html
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