Spring fever (or feverish springs)

[A440A]

Dave writes, to "ED"  ( I know, the other Ed, but still............)
<<I'm talking about the kick you feel if you still have your finger on the
key as it rises after checking.  Most players would have their finger
off the key at this poing and will not feel it. >>

    I think Dave is referring to spring recoil here when he says "kick".  Me
too.  
However, in a lot of legato play, the hammers come off check while the finger
is still slowly lowering the damper.  It is in this style of play that the
spring recoil becomes objectionable.  
    The feel of spring resistance,  (via the repetition lever and jack), as
felt in the key at the point of let-off is, IMHO, best reduced to a minimum.
For this reason, I like to have the jack tail and the repetition stop pad both
hit their respective stops simultaneously.  This allows the maximum
sensitivity of the action at the softest levels of play.  
     Other factors influencing this feel are the position of the jack under
the knuckle, the tangential  relationship of the jacks position to the
knuckle, and the frictional characteristics of the sliding surfaces, ( jack to
knuckle).  The radius of the leading edge of the top of the jack can also be
very important in how this point of release is perceived.  
Regards, 
Ed Foote