center pinning question

[Willem Blees]

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




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