Why?

[David ilvedson]

Roger,

Yes, yes, yes...now what kind pinning friction do you go for.  If 
I'm using a swingtest I like 5 to 6.  Rick Baldassin is really in 
to tighter pinning claiming the same things you are talking 
about.  Firmer pinning means a more controlled attack on the 
string i.e. less wobble.  Obviously if one side is looser than 
the other you will get wobbly but if both sides are to loose 
you'll get wobble.

David Ilvedson, RPT

Date sent:      	Thu, 03 Jun 1999 19:08:26
To:             	pianotech@ptg.org
From:           	Roger Jolly <baldyam@sk.sympatico.ca>
Subject:        	Re: Why?
Send reply to:  	pianotech@ptg.org

> Hi Richard,
>              I just knew some one would pick up on that statement, I'm
> smiling.
> If you have had the opportunity to study slow motion films of a travelling
> hammer you will notice several things,  1. The shank starts to bend before
> the hammer starts to move. 2. the hammer does not travel straight to the
> string but tends to wobble like a drunken sailor in flight. This wobble is
> far more pronounced on the angled hammers.
>  I have just completed a test on a Yamaha U1 about 20 years old that was
> showing the phasing problem at the bass tenor break. Hammers were well
> traveled and nicely mated to the strings as well as evenly voiced. Both non
> speaking lengths of the strings were braided to remove this item from the
> equasion, the strings were seated to the bridges, and the bridge pins were
> lightly tapped to eliminate false beats.
>  Problem was still there, and I had duplicated John Woodrow's problem. I
> then changed the centre pins, Making sure that about same amount of
> friction was on each side of the flange yoke.  Yureka!!! the problem
> disappeared.
>  I think what is happening, is that with a slightly loose pin the flight of
> the hammer is much more erratic, causing it to strike one string before the
> other, therefore giving the phasing effect.
>  I change a lot of centre pins in the killer octave region of grands prior
> to voicing, and can hear the changes in harmonic structure long before the
> centre pin starts to give the classic audiable click.  Down at the
> bass/tenor break there is so much going on sound wise, that I have never
> previously thought to check.
>  Another thought for the reason on noticing it more on angled hammers is
> that the weight not evenly distributed down the centre line of the shank,
> adding to the wobbly flight pattern.
>  Hope this sheds some light on your question.
> regards Roger
> 
>  
> 
> 
> 
> At 11:09 AM 5/9/99 +0200, you wrote:
> >
> >
> >Roger Jolly wrote:
> >
> >>
> >> Similar instability can be noticed at the bass/tenor break, with the
> >> addition of phasing due to the critical nature of angled hammers.
> >> I'm sure others will add more reasons, but I would think this is the
> >> primary cause.
> >> Regards roger
> >
> >I'd like to hear more about this phasing in relation to angled hammers..
> >
> >Richard Brekne
> >Sydneskleiven 1
> >5010 Bergen, Norway
> >
> >E-mail Richard Brekne
> >Richard Brekne Website
> >
> >
> >>
> >>
> >> At 05:41 PM 5/8/99 -0400, you wrote:
> >> >I am wondering who can provide a definitive answer to the question of why
> >> most
> >> >pianos seem to go out of tune the most at the treble break.  I have heard
> >> >several versions of answers, and would like to hear from the best.  I am
> >> new to
> >> >the List, and inquiring minds just have to know!    Clark Sprague
> Greenwich,
> >> >Ohio
> >> >
> >> >
> >> Roger Jolly
> >> Balwin Yamaha Piano Centres.
> >> Saskatoon/Regina.
> >> Canada.
> >
> >Attachment Converted: "c:\eudora\attach\ReWhy.htm"
> >
> Roger Jolly
> Balwin Yamaha Piano Centres.
> Saskatoon/Regina.
> Canada.
> 


David Ilvedson, RPT
Pacifica, CA
ilvey@jps.net