center pinning question

[Allen Wright]

Willem,

I did indeed carefully measure the pins, of course (since I was  
seriously puzzled by this phenomenon) - and they were exactly the  
same size, namely .051.

The idea of pin wear is what I suggested in my original posting as  
the third possibility I could think of; and by the way, are center  
pins then, in fact, plated? I've always assumed so, but if they're  
made of "nickel silver" as the supply catalogue says, are they nickel- 
plated on silver? Silver plated on nickel? Or are they solid chunks  
of some alloy called "nickel-silver"?

Sorry for what may sound like dumb questions; it seems like something  
I should know after all these years. Or perhaps I knew it  
definitively at some point, and have forgotten it since; one of the  
joys of maturity, that you sometimes get to learn things a second time!

Allen


On May 15, 2008, at 3:36 AM, Willem Blees wrote:

> Allen
>
> Two theories.
>
> One, just to be on the safe side, did you actually measure the new  
> pins to make sure it is the exact same size as the old pin? Or are  
> you just reaching into your box of pins, and pulling one from a box  
> that says size (51), or whatever?
>
> Two, when you measured the old pin, did you measure the middle of  
> the pin, or at the end? I'm just guessing here, but I wonder if  
> perhaps the ends of the pins are just slightly smaller where it was  
> in contact with the bushing cloth. Perhaps the nickel plating, or  
> some other outer surface of the pin, was "eaten" off by the felt,  
> or what ever was or is in the felt. So when you measured the middle  
> of the pin, it is the same size as your new pin, but the ends of  
> the pins are slightly smaller, which is why the bushing was loose.
>
> As I said, just speculating. Comments, anyone.
>
>
> Willem (Wim) Blees, RPT
> Piano Tuner/Technician
> Honolulu, HI
> Author of
> The Business of Piano Tuning
> available from Potter Press
> www.pianotuning.com
>
>
> -----Original Message-----
> From: Allen Wright <akwright at btopenworld.com>
> To: Pianotech List <pianotech at ptg.org>
> Sent: Wed, 14 May 2008 1:27 pm
> Subject: center pinning question
>
> In repinning an old (1930's) Steinway M, quite a few were loose. I  
> found that replacing the old pins with the exact same size (but  
> new) pins was producing just the amount of friction needed - and  
> even in some cases adding too much, so that I had to ream with my  
> "Mannino" burnishing files. Any theories on how that happens?  
> Something to do with the nap of the cloth changing in the process,  
> or perhaps the angle of the pin changing in the bushing, or (even  
> more unlikely) that somehow only the outer edges of the pin are  
> slightly worn on the old pins? (These are the various ideas me and  
> my colleagues were coming up with to explain the phenomenon).
>
> Thanks, and I'll take my answer off the air...   : )
>
> Respectfully,
>
> Allen Wright. RPT
>
> =
> Plan your next roadtrip with MapQuest.com: America's #1 Mapping Site.





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