A metallic sound from bridge pin/string?

[piannaman at aol.com]

Ed, Ric, collective Overmind of the list,
 
Thanks for the well thought out post.  It is indeed the left string.  I have been looking for an excuse to get a real downbearing gauge, and now I guess I have it (instead of the rocker gauge....).
 
Things I've done:
 
Needled lightly at the crown along the string groove
seated all termination points 
lifted and levelled 
seated
seated
seated again...
 
The thing that makes me think its the pin or something at that termination is that when I seat the string at that point, the sound goes away--for awhile.  So my thinking is that no matter how much I push the string down, it's popping right back into place.  Downbearing popped to mind.  I considered that overzealous planing may have occurred.  I'll try the shim.  Maple veneer, perhaps?
 
It's an afterwhine/zing.  It sounds like a sympathetic vibration from something else, but it's not there with either or both of the other two strings of the unison.
 
Descriptions are fairly useless, I realize.  Recording it will be difficult, but I may try it if I can't solve the problem to the customer's satisfaction.
 
Thanks again,
 
 
Dave Stahl


-----Original Message-----
From: ed440 at mindspring.com
To: pianotech at ptg.org
Sent: Sat, 30 Sep 2006 11:36 AM
Subject: Re: A metallic sound from bridge pin/string?


Dave-

First you will need to diagnose very carefully. Is it one string that is giving 
trouble, or all three of the unison?
Is it the left string? Is it possible the bridge was planed a little too heavily 
on the front edge before notching?  If so, with some clever mini-woodworking, 
you could add some wood to the bridge cap (maybe just a tiny shim).

Do you have a downbearing gauge to take measurements here?

Or is there something odd about the wire? Could a kink just behind the bridge 
pin be causing the trouble?

Before you do drastic work, you might change the hammer and see what happens. No 
hypothesis, just check it, since it's easy to do.  Maybe a hard place in the 
hammer?

You could probably slip a piece of veneer under the string to see if raising the 
edge of the bridge cap would help.

Enjoy!

Ed Sutton

-----Original Message-----
>From: piannaman at aol.com
>Sent: Sep 30, 2006 1:21 PM
>To: pianotech at ptg.org
>Subject: Re: A metallic sound from bridge pin/string?
>
> Patrick,
> 
>This strikes me as a very real possibility.  The string seems to be working its 
way back up the bridge pin for whatever reason.  Negative downbearing seems like 
a culprit.  
> 
>How would I go about increasing the downbearing for one note, though?  
> 
>Still feeling like a novice,
> 
>Dave Stahl
>
> 
>-----Original Message-----
>From: jpdraine at gmail.com
>To: pianotech at ptg.org
>Sent: Sat, 30 Sep 2006 6:22 AM
>Subject: Re: Re: A metallic sound from bridge pin/string?
>
>
>Dave, 
>With all the various suggestions about string seating and bridge pin 
>tapping & gluing, I'm surprised noone has brought up the possibility 
>of negative downbearing as a potential cause. 
>Good luck! 
>PS Is the customer complaining or is it just driving *you* over the edge? 
>Patrick 
> 
>On 9/30/06, piannaman at aol.com <piannaman at aol.com> wrote: 
>> 
>> Thanks, Larry. It's a grand with agraffes in that particular section. The 
>> sound goes away with pressure on the string at the front bridge pin. 
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