[pianotech] Easing Balance Holes : Kawai KG-1E

[Don Mannino]

Avery,

 

Well, that's because we're piano tuners, and we think of tuning pins' and
bushings' reaction to humidity.  They're different from key balance holes.

 

A hole in a piece of wood (not laminated) changes with humidity exactly like
the plug of wood that used to be in the hole.  So the hole grows a little
larger, though not symmetrically, when the piece of wood swells up and gets
bigger.

 

With tuning pins, you have cross-laminated wood that can't move much, plus
you have wood fibers within the hole compressed tightly against the pin.  So
those inside the hole surface fibers swell when the humidity is high, making
the pin gets tighter.

 

All it takes is one time prepping a piano under one condition, then seeing
the piano again in the opposite, and this becomes quite apparent.  Take it
from Houston to Denver, and hoo boy, those key balance holes get tight!

 

Don Mannino

 

 

From: pianotech-bounces at ptg.org [mailto:pianotech-bounces at ptg.org] On Behalf
Of Avery Todd
Sent: Sunday, October 09, 2011 5:01 AM
To: pianotech at ptg.org
Subject: Re: [pianotech] Easing Balance Holes : Kawai KG-1E

 

Don, 

 

What am I misunderstanding here? Shouldn't it be just the opposite, ie,
freely drop in dry weather and barely slide during humid? If it barely
slides during dry, it's going to tighten up more during humid and be too
tight. Right? Straighten me up here if I'm wrong. Hmmm.. 

 

Avery Todd

Houston, TX 

On Sat, Oct 8, 2011 at 4:38 PM, Don Mannino <donmannino at ca.rr.com> wrote:

Paul,

The ideal easing is for the key to slide down slowly, but keeping in mind
the humidity is important.  In variable climates like yours, during very dry
weather ease it so that the key barely will slide back down the pin.  During
humid weather, it should fall freely.

This method makes the keys with more lead weights slightly tighter.

Don Mannino

-----Original Message-----
From: pianotech-bounces at ptg.org [mailto:pianotech-bounces at ptg.org] On Behalf
Of Paul Milesi
Sent: Saturday, October 08, 2011 1:00 PM
To: PTG Pianotech List
Subject: [pianotech] Easing Balance Holes : Kawai KG-1E

I am working on a 1991 Kawai KG-1E (5'4") in a church.  Among other things,
I replaced key bushings.  While easing keys, I realized that the balance
pins are installed perfectly perpendicular to the rail, rather than angled
back.  Should this change my approach to easing the balance hole?  I was
taught to lift the front of the key anywhere from 1/4" to 1" while the back
of the key rests on the back rail, and to ease for free fall of the key.  It
seems to me that on any piano, at some point lifting too far and easing to
allow for a freely falling key will cause chucking (pulley key).  In this
particular case, does having the pins perpendicular require less, or no,
lifting at the front, but rather lifting front and back of the key to check
balance hole fit?

Hoping Don Mannino might be watching....

Paul Milesi RPT
Washington DC
(202) 246-3136 <tel:%28202%29%20246-3136>  Cell/Text
paul at pmpiano.com
http://www.pmpiano.com <http://www.pmpiano.com/> 





 

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