SV: 1879 Steinway A (jacks)

[David M. Porritt]

Ed:

This is the way I have set repetition height since learning it from Bill Garlick many years ago.  I think this is what they call "rolling the flys" at the Steinway factory.  This gets the jack right where you want it regardless of the wear on the knuckle.  

Speaking of knuckles, I had an older "B" the other day with lots of hammer return noise.  Investigation showed that it was the hard knuckle returning on the repetition lever.  I decided to squeeze the knuckle front to back to flex it a little.  I fully expected to have to reset the hammer line when I was finished (like after bolstering) but the hammer line didn't change at all (at least to the naked eye).  The noise was MUCH better.  I had never taken that tack before for knuckle noise.

dave


__________________________________________
David M. Porritt, RPT
Meadows School of the Arts
Southern Methodist University
Dallas, TX 75275
dporritt@mail.smu.edu


----- Original message ---------------------------------------->
From: <A440A@aol.com>
To: <pianotech@ptg.org>
Received: Tue, 21 Sep 2004 19:53:18 EDT
Subject: Re: SV: 1879 Steinway A  (jacks)

>Greetings, 
>I wrote: 

>>         In regards to the jack's position, I would posit that the most

>>important thing is that it be no further under the knuckle than is

>required for  dependable actuation.  

>Richard writes: 


>>>Gotta dissagree. Too far out and the key will miss and you loose power. >>

>     Losing power is not dependable actuation!  If it misses, it is too far 
>proximal.  There is a point where the jack delivers full power, dependably.  
>Any position that is farther distal is wasted friction.  
> 
>Kjell writes: 
><< 

>I think Ed Foote meant the jacks position under the lever (not forwards

>or backwards). 20 years ago I learned at the Schimmel factory that the

>top of the jack should be positioned just a little bit under the lever

>arm (or more correct: the lever arm just a little higher than the top of

>the jack, "the thickness of a hair"). Some years later I learned the

>same at the Bösendorfer factory. And this weekend Sauter told us the

>same at the Nordic Convention in Denmark. << 

>    The problem with static dimensions like this is that they do not account 
>for wear in the knuckles.  I think the factory advice is somewhat compromised 
>to allow the greatest number of techs to get dependable repetition. However, I 
>think there is a finer refinement possible;  to wit, (or to half or quarter 
>wits, whoever gets involved like me in such obtuse obsession with such abstruse 
>concepts.....)
>     I set the balancier height so that the jack can be felt to scrape the 
>knuckle as it is softly triggered by a finger on the tender, and will return 
>under simple spring pressure.  This assures me that there is no lost motion.  
>Having the balancier carry as much weight as possible, with the jack still in 
>contact, assures the most transparent escapement at ppp levels.  Since I set 
>let-off as close to the string excursion zone as possible, this combination(along 
>with drop set at the same distance as let-off) gives the greatest sensitivity 
>possible without compromising power or repetiton.   I also favor springs that 
>cannot be felt in the key when the hammer is released from check.  
>Regards, 

> 





> 





>Ed Foote RPT 
>http://www.uk-piano.org/edfoote/index.html
>www.uk-piano.org/edfoote/well_tempered_piano.html
> 
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