[CAUT] Kawai GS60 Bore distance

[Don Mannino]

Bob,

Kawai boards are "combination crowned" generally, although this has
changed over time and I am not sure how the GS models were made.  Curved
cauls are normal, but curved ribs have come and gone with different
models.

Mid-treble sustain could be bearing, and also could be bridge pin
problems.  So pluck the strings and compare the decay envelope with
played notes, check the bearing, and possibly lower tension on 1 string
and check the bridge pins.  Thin epoxy should be a good answer if they
are loose.

Again, I'm not as sure with the GS models, but light bearing loads are
common in Kawai pianos.  So finding overall positive bearing but with
low numbers is normal, especially if you measure back and front
separately.  The rear can be neutral to slightly negative, with the
front positive, and net bearing positive.  If bearing is too light and
the board still has measureable crown, then you can try lowering the
nose bolt 1/4 turn in the treble area.  I have had good luck "fixing"
some 7 foot RX grands this way.  Net bearing should be in the area of
.006 - .012 in this part of the scale when new, and may be more like
.003 - .008 now.

Hammer bore distance for all Kawai grand pianos since the 60s is 130mm.

Don Mannino
 

-----Original Message-----
From: caut-bounces at ptg.org [mailto:caut-bounces at ptg.org] On Behalf Of
Bob Hull
Sent: Tuesday, July 21, 2009 9:26 AM
To: caut at ptg.org
Subject: [CAUT] Kawai GS60 Bore distance


1.  I'm putting a new set of hammers on a Kawai grand.  I'm measuring
130 mm on hammer bore distance for this Kawai GS60 - does this match
their specs?

2.  Typically, how strong are Kawai soundboards?  Aren't they CC?  I'm
hoping these new hammers will help sustain return somewhat - I have
tried voicing and shaping to practically no avail.  These have already
been shaped a couple of times at least anyway so they're getting down
there.  It's had about 13 years of very heavy usage.
 I will measure downbearing later today.  Mainly from about Bb 4 up
through octave 5, maybe some of 6 are lacking in sustain quite a bit.  

Bob Hull