Upright loss of repetition

[piannaman at aol.com]

John, William, all,



I sent this before, but I think it got lost somewhere along the way...



Don Mannino once posted somewhere (Piano World maybe?) that Kawai
uprights operate better with no or slightly negative lost motion.? I've
set them that way, and they work well.? I try to set the "lost motion"
(found motion.....?) in the humid season so that the when the air
becomes less humid, they develop a slight amount of lost motion--the
fudge factor, if you will.



If I feel excess friction at the jack/butt interface I brush teflon powder onto the hammer butts.? Jacks may be hanging up.



I've found Kawai upright actions to work quite well.? What model is it?? Wood or ABS parts?? 



Good Luck,


Dave Stahl


 



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

From: William R. Monroe <pianotech at a440piano.net>

To: Pianotech List <pianotech at ptg.org>

Sent: Sat, 27 Oct 2007 8:08 pm

Subject: Re: Upright loss of repetition












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?


>?


> ?






 





Email and AIM finally toget
 


 

-----Original Message-----
From: John Formsma <formsma at gmail.com>
To: Pianotech List <pianotech at ptg.org>
Sent: Mon, 29 Oct 2007 4:55 am
Subject: Re: Upright loss of repetition










On 10/28/07, William R. Monroe <pianotech at a440piano.net> wrote:

> I don't understand.  When the jack trips out is dependent upon where the
> let-off button is set, right?  So, if ALL you did was file away felt, the
> jack still trips at the same time relative to keystroke, but too early now
> relative to let-off.  Picture the hammer, held at let-off, jack just
> starting to trip.  Now file away 1/2" of felt.  Let-off is now 5/8", but the
> jack still trips at the same point in the keystroke, yes?  Same clearance as
> before filing.

OK, yes, I think you are correct.  What I was saying has to do more
with how far the hammer rest rail is relative to the strings.  My bad.

> Ha!  You're using Bonetti's defence against me, huh?!

I thought it fitting, considering the rocky terrain.

> I will double check my blow/lost motion, etc. when I return.

I tend to be regulationally challenged.  At this point in my career, I
haven't done enough of it regularly to acheive "fluency."  I can
always figure it out, given adequate time.  One thing that helps me,
though, is knowing there aren't an infinite number of possibilities.
The more I do it, the better and faster it goes.

-- 
JF

www.ThisNovember5th.com
www.ronpaul2008.com



 


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