[pianotech] Bobbling hammers and jack spring pressure?

[Dean May]

I tuned a U3 today with a tendency towards the bobbling hammers with the
sustain pedal on. The damper spoon was lifting the damper a little when the
key bottomed out. I simply adjusted some lost motion out of the sustain
pedal so it lifted the dampers enough to clear the spoons. The difference
was significant, much nicer to play.

 

I learned that adjustment technique on this list a couple of years ago. To
restate: make sure that when the damper pedal is on, the keys do not
contribute towards any lift on the dampers. This is for a vertical piano
only.

 

The opposite is true for a grand. On a grand when the damper pedal is on the
keys should lift the dampers slightly off the tray. Otherwise if the pedal
raises and lowers the dampers off the key when the key is depressed, the
pianist will feel it. 

 

Dean

Dean May             cell 812.239.3359 

PianoRebuilders.com   812.235.5272 

Terre Haute IN  47802

 

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From: pianotech-bounces at ptg.org [mailto:pianotech-bounces at ptg.org] On Behalf
Of Carl Teplitski
Sent: Friday, January 23, 2009 7:24 PM
To: pianotech at ptg.org
Subject: Re: [pianotech] Bobbling hammers and jack spring pressure?

 

I tune many  Yamaha teaching pianos in our town, and almost all the new
Yamahas

exibited similar traits described herein.   First time tuning these new
pianos, I did some 

let-off adjusting.   Next time tuning , (3 months), same problem was there,
although I don't

know if the same keys were at fault, cause I really didn't take note the
first time, thinking

that problem should be solved. I just take a large screwdriver and bear up
on the letoff rail, 

and this usually tells me that that's the problem. Other times , I've
adjusted the capstans up

to make for less lost motion.  This worked, too.  Soooo, sounds like the
previous writer

says that it probably needs more than one adjustment, but several.  Think
he's right. 

I would like to know , if in fact,  there is a definitive answer .  (
springs ?? )

 

Carl / Winnipeg 

----- Original Message ----- 

From: Ryan Sowers <mailto:tunerryan at gmail.com>  

To: pianotech at ptg.org 

Sent: Thursday, January 22, 2009 5:49 PM

Subject: Re: [pianotech] Bobbling hammers and jack spring pressure?

 

My vote is for the damper springs. They are often set much stronger than
they need to be and do cause some resistance to a full key stroke during
gentile playing. I ran into a similar problem a while back and a compromise
between a little extra let-off, a tiny bit more key-dip, a weaker damper
spring, and timing just a wee bit later. Sometimes you can combine several
subtle adjustments to get the result your looking for. Ultimately I believe
this may be a geometry issue that these pianos might have. I was recently
having a conversation with Ed McMorrow about this and he claimed it had
something to do with the relations of the action centers and over centering
of the hammer. We hear so much about grand action geometry but not enough
about upright geometry. 

On Wed, Jan 21, 2009 at 8:22 AM, Gregor _ <karlkaputt at hotmail.com> wrote:

List,

is there a way to ease the jack spring? I have problems with a Yamaha P121N
upright that has bobbling hammers. The hammer butt is dancing on the jack
tip. All regulation measures are okay and there is enough aftertouch. I
suspect the jack spring being too strong. Any thoughts how to get it right? 

There is no lost motion, check is about 15 mm, aftertouch is okay and I gave
some talkum powder to the jack tip and the let off button. The only thing
that helped was to set the let off to 10 mm, but that´s not a satisfying
solution. The strange thing is that one could play without bobbling hammers
but something makes the player stop pressing down the key before the let off
point. A very subtile resistance gives the player a hint that the key is
pressed down now, but that´s not right. The player could and should press
further on. The strange thing is that this problem is new for a few days. I
should mention that we had very dry air last weeks and the customer has a
floor heating. Therefore I suspect a connection between this problem and the
dry air.

Any comments?

Gregor


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What can you do with the new Windows Live? Find
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-- 
Ryan Sowers, RPT
Puget Sound Chapter
Olympia, WA
www.pianova.net

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