Upright loss of repetition

[William R. Monroe]

Hi John,

Nope, adjusting blow distance is SOP for me on this job, along with lost 
motion.  I've wondered though, about this change.  Unless you are filing 
hammers past the grooves, the blow distance hasn't really changed pre-filing 
to post-filing.  It seems that it has changed gradually over the years, and 
only those little fingers of useless felt either side of the grooves are 
still at proper (original) blow distance, right?

Also, I'm unclear how filing away felt from the strike point affects the 
jack to butt clearance.  I don't see how that would be changed until AFTER 
you correct blow, and then it would be too great, not too little.  Or did I 
miss something?  I would think it would be let-off that is now a problem 
(too great) and probably checking, and................

William R. Monroe



----- Original Message ----- 
From: "John Formsma" <formsma at gmail.com>
To: "Pianotech List" <pianotech at ptg.org>
Sent: Saturday, October 27, 2007 8:41 PM
Subject: Re: Upright loss of repetition


> On 10/27/07, William R. Monroe <pianotech at a440piano.net> wrote:
>
>> Any other thoughts on the matter?
>
> If you haven't set the proper blow distance for the reshaped hammers,
> you can have this problem.  (Assuming all other variables remain the
> same.)
>
> If felt is removed, blow distance is increased.  This necessitates
> shimming the hammer rail in order to restore proper blow distance.
> Because...if the key dip remains the same, and the blow distance is
> greater, the jack will have less clearance to return under the butt.
> (The key will have to come up more to allow the jack to reset under
> the butt.)  Thus, repetition is reduced.
>
> This is what I'd try first.  If it doesn't work, that wasn't the
> problem.  <g>  (You can try a few samples on the worst offenders to
> keep you from proceeding in the wrong direction with the whole
> action.)  Once you set the proper blow distance, you will need to
> adjust for correct lost motion.
>
> -- 
> JF
>
> www.ThisNovember5th.com
> www.ronpaul2008.com
>
>