[pianotech] key position at rest

[Richard Brekne]

Hi Paul

David has it right. The idea of leaning the capstan forward instead of 
backwards has to do with the friction between the whippen heel and the 
capstan. You have two parts both moving in arcs, and at half way through 
the key stroke, these arcs should be touch.  The idea is that this 
condition yields the least friction between the two parts. So in order 
for this to happen, the <<point>> of the capstan and the <<point>> of 
the whippen heel should be exactly parallel and on the same line at half 
blow. It makes good sense but as to whether or not one can measure a 
difference ... well I haven't actually measured such things myself... so 
I wont presume to answer that.

Why they angled them backwards I'm still unsure of.  I've thought at 
times they must have thought they were getting more leverage out of the 
lever.  That doesn't really quite wash when it comes down to it.  You 
put a vertical force on an angled input to a lever and you get into 
vectors... and everything is moving anyways.  Like I said to begin 
with... I don't really understand what they were thinking about when 
they angled them backwards.  Still, the folks what designed things back 
then were not exactly idiots.  Might be nice to know.

Cheers
RicB

        David:
         
        Recalling would presuppose a calling! :-)
         
        This bit about Ron Overs' action design is news to me. Does Ron 
        offer (is this really old news?) insight into his reasoning and
        does he have  demonstrably measurable results? If this is an
        archive matter, just say so, and  I'll do the work! :-)
         
        Thanks,
         
        Paul