Tuners--Broken Pins

[McNeilTom@aol.com]

I've never had a tuning pin break, nor found any broken.  However, Laurel
Rivers, RPT, then my assistant at SUNY Fredonia (now head technician) broke
one.  Baldwin SD-10 concert grand (one of the earliest specimens with some
unusual design features); loose tuning pin in the low bass; shimmed with
thick sand paper [maybe 60-D]; resulting torque was much greater than the
original equipment tuning pin could take!
We were able to drive the pin out through the bottom of the pinblock
 __supported very well from below__  .  The stub of the tuning pin was an
exceedingly tight fit and it was very difficult to drive it through with a
big hammer and appropriate punch.  The pin had broken at the becket hole,
where I suppose the strength is much reduced from the rest of the pin.  I
don't think the tuning pin extractor would have worked in this case, due to
(1) extreme torque required, maybe 600 in-lbs, and (2) very close working
clearances.

Moral of the story: if shimming a high-density multi-laminated pinblock, use
 __thin__ material; a little is enough, more than that is too much!

Broken agraffes:  I've seen a couple dozen in thirty years.  Averaging one a
year?  But sometimes two or three in the same piano, mostly S&S.  But then, I
have done a great deal of grand rebuilding and have probably seen more than
my share.  Over the years one makes or acquires a few special tools for these
repairs.  The challenge is to remember where you put 'em away!

  -     Tom McNeil, RPT     -
Vermont Piano Restorations