your punching comments

[V T]

Hello Andre, David and List,

I have new green Pianotech front rail punching, a
Baldwin punching from around 1980, and a sample of
Andre's conical Wurzen felt punching.

I have not done an "installed" evaluation yet, so I
can only comment on how they compare when you squeeze
them.  Here are my comments, after measuring
compression:

- The Baldwin punching compresses about 1 mm before it
bottoms out.  The "bottoms out" point is subjectively
chosen but it happens at around 1.5 kg of weight.  The
punching is 0.75" (19mm) in diameter.  It is not
conical, and it's woven.  There is significant memory
in this punching - after releasing the pressure, it
springs back 0.85 mm and then it slowly relaxes to its
normal uncompressed height.  That means that it
retains a temporary residual compression of 0.15 mm or
0.006".

- The green Pianotech punching compresses 1.1 mm. It's
soft on initial contact.  It doesn't bounce back up
forcefully after the pressure is released.  It is the
quietest of the three on impact.  It's 0.875" (22mm)
in diameter and it is woven.  This punching also has
about 0.15 mm of residual compression right after it's
released.  My guess is that it doesn't offer as crisp
a feeling at initial contact, but it does absorb the
energy quite well - if that is what we want in this
application.

- Andre's punching compresses 0.75 mm (the least of
the three), but it has a remarkable springiness. It
springs right back after pressure is released.  My
guess is that the initial contact with the key is well
defined. Because the punching springs back so readily,
I would guess that it doesn't absorb as much energy as
the Pianotech punching. Instead, it acts as a spring
and it probably returns a higher portion of the energy
back to the key (on the way up).  This punching is not
woven, the top surface is 23mm and the bottom surface
is 24mm in diameter.  The residual compression on this
punching is only about 0.05 mm!  This certainly would
be the easiest one to regulate with.

Anyway, these are just measuements, and the real test
for me will be after installation.

Vladan


The firmness, caused by the density/homogeneity of the
felt and, especially, the natural elasticity caused by
the high quality wool fibers create a firmer touch
than most punchings, without causing the feeling of
unpleasantness you described from the Baldwin
punching.
I do not know the pear green punching you describe, so
I am not able to compare them, but in the opinion of
our customers, and myself, there has not been, yet, a
conical punching like ours that makes for such a
precise after touch, and after touch is for me the
most important issue when it comes to fine regulation.



		
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