center pinning question

[Allen Wright]

p.s. Willem,

I did try measuring the ends of the pins, when one of my shop  
colleagues offered this idea as his theory. It's tough to measure  
just the very end with the micrometer, though! I didn't feel  
confident I was getting a good reading. It'd be interesting to look  
at them under the microscope, though, and see if any wear was apparent.

I wonder if anyone else thinks that the pins themselves wear like  
that? Like water wearing away stone, year after year...

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.

t




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