Rolling to Pitch

[Robin Blankenship]

Ron,

Are we speaking of the same effect here?? I was referring to what appears to 
me to be your comment about the bridge PINS themselves becoming somewhat 
'flattened" by the sliding wire. Are you talking now about the bridge cap 
instead???

Thanks,
Robin

----- Original Message ----- 
From: "Ron Nossaman" <rnossaman at cox.net>
To: "Pianotech List" <pianotech at ptg.org>
Sent: Saturday, August 19, 2006 5:01 PM
Subject: Re: Rolling to Pitch


>
>> Interesting point you raise about the bridge pin contact area increasing
>> over time.....are you suggesting that it is or could be a good idea to
>> very closely look for this when doing restringing and possibly replace
>> the bridge pins in toto??? I had not heard this before but it surely
>> sounds very reasonable.
>
>
> Robin,
> I found it... Here's a photo of the kind of notch edge
> compression and pin damage you'll find. Here, a straight
> length of wire is pressed into the string groove at the notch
> edge for illustration. Note the angle it assumes relative to
> the bridge top, and how the notch edge is crushed below the
> point you would think the string is capable of reaching. You
> can also see grooving in the near bridge. These (and loose
> pins) are largely artifacts of the cap changing dimension with
> humidity swings, and the reason that seating strings to
> (sometimes) clear up false beats is of only temporary affect
> at best, and doesn't fix the problem.
>
> Recapping with something like this - 2nd photo - eliminates
> most of the problems.
> Ron N
>