Knuckle question

[Stephen Papastephanou]

Hi again,

I respectfully disagree with what Rick states below.
He states:
 
' To begin 
> with older knuckles developer other problems then just a worn surface.
> The felt core gets mushed up, the leather loosens around it and you get
> friction problems up the pattootey.'

There is no 'front ' or 'back' indicated in replacement knuckles because
there isn't any.
It would be virtually impossible for the leather on knuckles in a piano of
some quality become unglued, or be of different consistency on either side.
At least in the Yamaha, the leather is well glued and very stable with a
solid felt core undamaged by the wear on one side.

It is not the cost of new knuckles that is the problem, but the fit and
function, that can become a major headache, unless the knuckles are obtained
from the piano factory, and are identical to the original. Is it necessary?

The method I have suggested, i.e., turning the knuckles around, can be done
on the spot, the fit is of course perfect, (needing a drop of glue to stay
and snap in place) and since the hammer flange, shaft complex does not have
to be taken off the action, no realignment of the hammers to the strings is
necessary, provided of course that the hammers do not need to be replaced.
(However there is a good probability that they will need to be replaced
also, as they might have worn off before the knuckles did, but if one is
lucky, and they do not need to be replaced, the job becomes very simple).

Needless to say that one should make sure that the jack is in the correct
position, and that it's relation with the repetition lever is correct
allowing the knuckle to rest on the repetition lever etc., and was not
altered by a previous adjustment/s to compensate for the worn knuckle, as it
was gradually wearing out.

Further, the repetition spring, let off, drop, etc. should be immediately
brought back to specs, in that order, since the let off will surely change
when the knuckles are turned around and the jack hits now a thicker leather.

You can examine the knuckles, carefully, and you will see that I am probably
right. If they are damaged as Rick describes, then by all means replace. You
cannot obviously use damaged knuckles.

All the best and good luck

Stephen Papastephanou


On 12/3/06 1:21 PM, "RicB" <ricb at pianostemmer.no> wrote:

> Hi Larry.
> 
> In reply to the response to your post included below:
> 
> Leather on knuckles is not the same in both directions. The nap of the
> knuckle leather offers different resistance turned one way visa vi the
> other. If first you are to remove an old set of knuckles... it is
> useless to bother refitting these in the opposite direction. To begin
> with older knuckles developer other problems then just a worn surface.
> The felt core gets mushed up, the leather loosens around it and you get
> friction problems up the pattootey.  New knuckles do not cost much and
> will give you many fold return in terms of improved performance.
> 
> The replies you've gotten from Ed, Stéphane, and John deal with your
> question appropriately enough so I'll leave their good advice to stand.
> 
> Cheers
> RicB
> 
> 
>> List... I have a set of knuckles to install and the wood core is
>   slightly
>> narrower than the slot (it reaches the bottom). Is it acceptable
>   to install
>> and let the glue fill in the gap or should I shim it with paper
>   or anything
>> else? Or is it unacceptable to have a wood core that isn't snug?
>   Thanks for
>> your help.
>>  
>> Larry Trischetta
>> Chapter 186
>>  
>> 
>   Why not use the original knuckles? Just turn them around, so that
>   the jack
>   will hit virgin territory after they are replaced in the groove. (Unless
>   there is something else wrong with them)
>   If you notice, it is the front half that gets worn in a knuckle.
> 
>   S.P.
> 
> 
> 

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