Flat rollers

[Mike and Jane Spalding]

Last week, after I re-installed a cleaned/lubed/regulated action, the owner commented that the "ka-thunk" was much reduced:  that big bump at let-off which results from jack/knuckle friction, flattened knuckles, and jack too far under the knuckle.  Got me thinking a little (only hurt a little bit..)  her knuckles were well flattened from 35 years of use, yet the feel of the letoff after regulating the jack position was not too bad.  I have a theory, in two parts:

1.  neglecting the jack position, and allowing it to settle further and further under the knuckle accelerates and exacerbates (makes it worse) the flattening of the knuckle.

2.  when regulating the jack position under flattened knuckles, you can bring the jacks out a little further without risking loss of power, and compensate for the flattening.

Of course, I'm basing this on rather limited experience.  Will this come back to bite me after it's been played for a while?

Mike Spalding

 


----- Original Message ----- 
From: Robert Goodale <rrg@unlv.edu>
To: <pianotech@ptg.org>
Sent: Wednesday, March 13, 2002 11:11 PM
Subject: Re: Flat rollers


> Hmmmmm, amateur night.  Okay, fair enough.
> 
> The "rollers" are called "knuckles", and yes they supposed to be round. 
>  There is a popular remedial repair that I have recently become a big 
> fan of, that being to weave yarn into the core felt to bolster it up and 
> make it round again, (or at least somewhat round).  You can lightly sand 
> the leather to remove much of the grooving. Regulation will be required. 
>  That of course is another subject.  I'm sure many members of this list 
> are just dying to hop in and continue this discussion.
> 
> Rob Goodale, RPT
> Las Vegas, NV
> 
> 
> 
> Gerald Posey wrote:
> 
> >All the rollers on my hammers are flattened and/or grooved. Is this a
> >serious problem?  Is there a fix besides replacement?  This is my own piano
> >(Heintzman Baby Grand) that I'm working on as a hobby.
> >Thanks,
> >Gerald
> >
> 
> 
>