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. -------------- next part -------------- An HTML attachment was scrubbed... URL: https://www.moypiano.com/ptg/pianotech.php/attachments/20080515/fc2ba4a9/attachment.html
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