Ditch the tuning pin bushings

[Joseph Garrett]

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Bill and List,
Many years ago, I rebuilt a Kimball, 6'?" Grand. It had tuning pin =
bushings, which were larger than standard and they were made out of =
laminated maple! I duplicated this when I redid the piano. It was a =
dream to tune. I might add, I used pin driving fluid, so that the =
threads of the t. pins would not "ream" the bushings. At the same time, =
another top quality rebuilder, friend of mine, did another Kimball with =
the same configuration. He opted to put standard plate bushings in. That =
piano was, and still is, a bear to tune! My conclusion, then and now, is =
that if the proper material is used for plate bushings, (NOT endgrain, =
non-descript wood), they will enhance the t.pin stability in it's axis =
and tuneability will be ensured.
One thing that should be noted, is that tuning pin bushings change the =
lines of force within the frame/plate/pinblock structure. If one is to =
draw a side view of a piano structure, (ie plate w/pin block, tuning pin =
and string, etc., then draw the lines of force and the pivots therein, =
one will find that, with a plate bushing the direct line of force is =
directly into the plate and not in the pin block. Without the plate =
bushing the direct line of force is directly into the pin block! It must =
be assumed that in this example, the tuning pin MUST be tight in the =
plate and around the tuning pin. Of course, the standard plate bushing =
does not meet this criteria.=20
Just some more food for thought. And yes, Del, I know you don't agree. =
Methinks too much brainwashing from your days at Baldwin. [grin] :-)
Regards,=20
Joe Garrett, R.P.T.
  ----- Original Message -----=20
  From: Billbrpt@AOL.COM=20
  To: pianotech@ptg.org=20
  Sent: Friday, May 11, 2001 8:33 AM
  Subject: Re: Ditch the tuning pin bushings


  In a message dated 5/11/01 10:01:52 AM Central Daylight Time,    =20
  Erwinpiano@email.msn.com (Erwinpiano) writes:=20


    My solution was to fully fit the block with a good plate fange =
contact=20
    and eliminate the bushing.  The piano tunes like a dream(Bolduc =
block)yeah=20
    baby. Enough said?=20


  Back in the late 1070's and early 1980's when I was interested in the=20
  rebuilding end of the business, many people were putting plate =
bushings in=20
  Steinways.  The word from Steinway at the time (and probably still is) =
was=20
  exactly the same reasoning that you put forth here, Dale.=20

  My only question about that is how far the tuning pin coil ended up =
being=20
  from the top of the pinblock.  In some cases, it seems to me, the lack =
of a=20
  plate bushing really creates a bad "flagpole" effect.  Couldn't a well =
fitted=20
  pinblock *and* good, hard maple plate bushings make an even better=20
  arrangement than simply one or the other?=20

  What's your and any others opinion on that, please?=20

  Bill Bremmer RPT=20
  Madison, Wisconsin=20

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