sluggish upright jack

[Dave Nereson]

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  ----- Original Message -----=20
  From: Eliot Lee=20
  To: pianotech@ptg.org=20
  Sent: Thursday, June 14, 2001 1:08 AM
  Subject: sluggish upright jack


  Hello,

      I had an old upright piano (Ludwig) with very sluggish jacks =
affecting
  repetition particularly in the high trebel.  Could this be from the =
coiled
  jack spring?  I lowered the capstan and eased the keys still didn't =
help
  much.  I noticed that there were no leads in the keys.

      Is this a sign that the wippen or the jack should be repinned?  =
What
  about treating with protek?

  Thanks for the help.

  Eliot Lee

  If there's enough lost motion to allow the jack to return under the =
butt, even when releasing the key slowly and with the damper pedal down, =
then there should be no need to lower the capstans.  If the jacks are =
sluggish, it wouldn't be from the springs, but because of tight pinning. =
 Remove a few wippens with sluggish jacks, disengage the springs and =
shake the wippens to see if the jacks flop around by their own weight.  =
If not, then yeah -- Protek, water, or  water & alcohol, zapping, or =
repinning.  Another thing that sometimes makes jacks sluggish and is =
elusive to figure out is a humped contour to the butt leather, that =
doesn't let the jack slide easily back under the butt, and in these =
pianos, sometimes you're forced to introduce too much lost motion just =
so the jacks will return.  Another problem could be that the keys are =
balanced wrongly or too heavy in front so that the weight of the action =
parts isn't enough to make them return all the way up.   --Dave Nereson, =
RPT, Denver


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