1890s WNG Action Geometry

[A440A at aol.com]

Jon writes: 
<< Once ideal regulation specs are configured, you can manipulate FW to 
target BW.
One would get a really low KR if one were to establish BW via KR with 
a heavy SW. Once you get the mechanism operating properly and the BW is too 
high, consider
lowering SW, increasing FW or installing wippen assist springs.>>

Greetings, 
     I agree, and would add a couple of things. There is a point where the 
capstan is too close to the balance rail pin and the KR begins to slow down the 
repetition, simply because the inertia of the FW is more than the spring, 
fulcrummed against the SW, will quickly return it.   So, there is a limit to how 
much leverage you can give the key in an attempt at overcoming SW.  This shows 
up on even light keys!   
    The moment arm of the knuckle to pin distance is where you can 
dramatically change the overall action ratio without decreasing the key return speed. 
However, the price of lower DW via the longer knuckle distance is increased 
keydip, which has its own limits.  These limits can be ameliorated by shortening 
the blow, which reduces power and control, or accepting less aftertouch, which 
demands greater consistency throughout your regulation procedure.  
    Repetition springs can be of great help in poorly designed actions, but 
their use is limited to around 10 or so grams, (for maximum repetition speed).  
If you need more than that, it is time to look at SW and knuckle distance.  
Regards, 


Ed Foote RPT 
http://www.uk-piano.org/edfoote/index.html
www.uk-piano.org/edfoote/well_tempered_piano.html