Asian Hammer Butt Spring String Friction

[Dave Nereson]

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  ----- Original Message -----=20
  From: Farrell=20
  To: pianotech@ptg.org=20
  Sent: Wednesday, April 23, 2003 3:58 PM
  Subject: Asian Hammer Butt Spring String Friction


  Asian Hammer Butt Spring String Friction - say that 3 times real =
fast........

  Problem: Renner Asian-type upright hammer butts with the integral =
spring and flange cord and steel plate that retains the flange center =
pin. The flange cord forms an acute angle that faces the width of the =
steel center pin retainer. When the butt is at rest, the flange cord is =
a millimeter or so away from the edges of the steel plate. As the hammer =
is propelled forward toward the strings, the apex of the flange cord =
angle gets closer to the steel flange and so the opening of the angle =
gets smaller. Prior to the flange being parallel to the shank (which is =
pretty close to the position when the hammer would hit the string), the =
flange cord comes into contact with the edge of the steel plate and for =
the short distance to the flange aligning with the hammer shank, the =
flange cord drags along the edge of the steel plate.=20

  I can feel the resistance in the flange. I can't imagine it should be =
like that. I just bought these hammer butts from Renner. Has anyone ever =
noticed this before? Does this occur on Yamahas? Any thoughts on how =
this might affect performance? I'm inclined to reject these hammer =
butts, but I've been know to obsess over trivial matters before (good =
enough won't cut it here). Any thoughts?

  Terry Farrell
   =20
  _______________________________________________
  pianotech list info: https://www.moypiano.com/resources/#archives

  Yes, I've encountered this, but it was in a piano that was also =
mice-infested, and I thought the mice were chewing the spring loops, =
which they may have been.  I dunno, maybe the cords need to be made of =
nylon or kevlar or some other space-age material.  Or all the butt =
plates need to be rounded off and polished.  Or get butts with longer =
spring loops.  There are Schwander-type butts without the butt plates, =
also (conventional pinning).  Haven't noticed the problem on Yamahas -- =
maybe their loops don't rub.  Don't Kawais and other Asian pianos have =
the same type butt?  I doubt the friction is enough to affect =
performance.  Certainly anyone who would notice that miniscule an amount =
of friction should be playing a grand (?).    --David Nereson, RPT

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