[CAUT] tight balancier

[David Skolnik]

Wimn'Edn'Ricn'all -
I think your right.  I may have been thinking of the effects of 
diminished key dip. However, as Ric and Ed point out, with the jack 
moved forward, the timing of the jack contact will change, meaning 
that the singular feeling achieved by the simultaneous (or virtually 
so) contact of the jack tail and the drop screw, is then staggered, 
thus extending and distorting the perception of let off.  It's could 
be argued, perhaps, that, in soft playing, the finger reacts 
differently to that 'extended' let off and increased friction, thus 
delivering less energy to the hammer than intended, with the 
resulting diminished force to achieve checking.  It's quite a reach, 
I admit, but never underestimate the power of defensiveness to 
stimulate creative thinking.

Ed Foote added the friction of the rep spring in the "grub", either 
from dirt / gunk build up, or from a dimple being formed, over time 
by the spring.  This could contribute to poor checking by directly 
increasing the friction the hammer must overcome in its downward 
movement, by generating the same finger response as described above, 
or a combination of the two.

Meanwhile, I thought of a few more checking-affecters:

1)Tails mis-faced to backcheck.  VERY common to find them out of 
plane in angled hammer sections  One side of tail contacts backcheck 
before other, resulting in very little actual  surface interface.
2)Backcheck wire stiffness.  The new Steinway wires are ...(your 
choice of adjective) stiff.   I think it's a mistake on five counts, no three.
One - Harder to regulate
Two - Transmit shock of hammer check to finger
Five, no Three - Minimizes spring function which, along with 
complementary surface facing, is the fundamental mechanism creating 
checking.  Imagine, for example, a backcheck wire with infinite 
stiffness. Checking would become a function of backcheck felt and 
leather resilience, surface angle interface, and surface texture 
interface.  Eliminate the remaining resilience, and you are left with 
surface geometry.  (It becomes clear that "roughing" the tails is a 
Band-Aid -potentially destructive- for other issues.)

Wim, I'm choosing to ignore your second question, for the moment:
>Does not checking on a medium to soft blow, without too much bobbling, effect
>the feel of the piano?

since the degree to which the problem is noticed is distinct from WHY 
it is happening.  To that question, I don't believe repinning the rep 
levers is your answer. It's not logical.

Flash! Here's another I think we didn't mention:  Bedding the 
keyframe.  Oscillation there could affect checking reliability.

Absent actually being there, I'd like to see a thorough check list of 
all the things we've mentioned...pictures would be, niice.
Exhaustive measurements would help. I don't know if it would work, 
but you could try using gram weights (dampers lifted) to see at what 
force the checking works or fails.

Last flash!  I wonder about the dampers.  If the checking is tenuous, 
with little spring in the system (stiff wires and hard backchecks), 
could the impact shock from a falling damper interfere with the grip 
of the check?

There IS an answer out there.

David Skolnik

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