[pianotech] problem in mating hammers to strings

[tnrwim at aol.com]

I feel to see if all the strings are in the same plane.  I 
on't like the idea of the bubble level because if the floor 
sn't perfectly level and the plate isn't perfectly level, or if 
he holes in the agraffe aren't perfectly level, you're getting 
 false indication.

David

Before leveling the strings with the bubble gauge, put it on the plate. If you see the bubble is to one side or another, then match that to the strings. But in all the pianos I've done this way,  I've only had one or two show that the plate, and/or piano, was not level. Your finger can't match what the gauge does. The gauge will tell you instantly which of the three strings is high or low. In most cases, it is the aggraff that's at fault. So you have to compensate by leveling the strings. That's the whole purpose of doing this in the first place. Once the strings are level, matching the hammers is much easier, and they will all look the same. 

Wim 

 






-----Original Message-----
From: David Nereson <da88ve at gmail.com>
To: pianotech <pianotech at ptg.org>
Sent: Thu, Mar 3, 2011 2:48 am
Subject: Re: [pianotech] problem in mating hammers to strings


    I feel to see if all the strings are in the same plane.  I 
on't like the idea of the bubble level because if the floor 
sn't perfectly level and the plate isn't perfectly level, or if 
he holes in the agraffe aren't perfectly level, you're getting 
 false indication.
   But regardless, when viewing the hammer line at the strike 
oint, it should appear as a straight line, so that's how I 
iled them.  I then held hammers against the strings, plucking 
he strings, and still found indications that the hammers had 
igh areas, or that a right string was low, and again, almost 
ll in the low tenor, and all on the right side of the hammer. 
o I used the plexiglass paddle with a thin (3/16") strip of 
andpaper glued to it, as demonstrated by either Andre Oorebeek 
r Ben Gac, I believe, to file down the hammer in the area that 
amps the strings that don't ring when plucked.
   This results in hammers that have a "step" in the strike 
oint surface, but using the end of a steel rule and a bright 
ight, I did not observe any low ("unlevel") strings in the 
orresponding unisons.  I still wonder if the pressure of 
olding an angle-bored hammer against the unison causes the 
hank to flex or the hammer to lean.
   --David Nereson, RPT
 


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