[pianotech] Ludwig Feigel Piano/Viennese Action Information Request

[David Doremus]

Hi John, thanks for that! I think we are basically in agreement although 
I would err on being just a whisker below the string at let-off. Most of 
my experience is with much earlier (5 8va) actions and the lightly built 
pianos tend to vary a lot in string height, like harpsichords do, and 
safety is a real consideration. I actually, at the owners request, 
installed a rail to allow individual let off adjustment in a Phillip 
Belt piano some years ago, because hammers that were fine one week could 
be blocking the next and shimming the hoppers (prells) out each time was 
painful. You can't trim the beak leather beyond a certain point or you 
lose any control of the return. The big, later Viennese are a whole 
different animal and I have only done 3 restorations of those and was 
always a little bemused by how thick and imprecise the beak leather was 
and how heavy the hammers are. You feel every gram of hammer weight 
right in the finger.

--Dave
    New Orleans

On 3/13/11 4:56 PM, John Delacour wrote:
> Hello David, the geometry of the action is such that the shank has 
> gone several degrees past the horizontal (hence the casting out of the 
> hammer head) when the hammer touches the string.  The "tail" of the 
> shank is therefore sloping down and tending to push the jack away and 
> escape; the jack is, as it were, hanging on by its fingernails. The 
> moment the hammer touches the string the jack must fly away even under 
> very soft blow, but the momentum of the hammer-head holds it against 
> the string for a tiny fraction of a second, just as happens in a 
> regular action and during that time the nose of the hammer moves just 
> a fraction along the string towards the player.  Both the "blocking" 
> and the "stroking" (or "sliding" as Jack calls it) are momentary 
> events, little more than tendencies in practice, but they exist.  Of 
> course it is necessary to regulate the fly in such a way as to prevent 
> actual blocking, but if you set the escapement at 1 or 2 millimetres 
> as you would on the French action, then quiet playing will be hit and 
> miss.
>
> JD

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