Heavy action

[David Love]

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Of course you are right.  Bad adding on my part.  Changing the BW by 12 =
grams puts it on the edge for inertia problems with what's given.  Two =
leads at C4 probably puts the FW around 25 depending on the position.  =
Adding 12 grams there could be a problem.  More data would be helpful.

David Love
  ----- Original Message -----=20
  From: Isaac OLEG=20
  To: Pianotech=20
  Sent: September 30, 2002 4:17 PM
  Subject: RE: Heavy action


  David,=20

  I believe you read a little too fast, it is 60 DW 45 UW that makes =
52.5 g Balance weight and a light 7.5 g friction.

  Even then, if all else is correct, adding lead may not cause problems =
I believe.

  The hammers may be very heavy to obtain this figure (I understood =
that, finally !)

  Regards.

  Isaac
    It's pretty hard to address this without a little more data.  Adding =
lead may not be a problem depending on the actual front weight.  The =
bass section will often take 4 leads without an inertia problem, but it =
depends on where they are.  Your C4 has a balance weight of 47.5 g.  To =
bring it down to 40 you will need to add 7.5 grams to the front weight.  =
With only two leads at this position it may not be a problem, but it =
depends on the overall front weight.  Balance weight at 40 is a =
reasonable target for this action.  That puts the DW/UW at 47/33 with 7 =
grams of friction.  I'd rather see the friction around 10 here so I =
would check the hammer flange pinning.  With 10 grams of friction, the =
DW/UW will be 50/30.  If the hammer weight/strike weight at this point =
is representative of the overall curve and the front weight is not too =
high, that will produce a nice feeling instrument.  Stanwood's system =
provides a nice method for analysis of these points.  The fundamentals =
of this system are available from the journal archives in a series of 3 =
articles written awhile back.  I highly recommend you become familiar =
with them.  It is perfectly designed to answer questions such as you are =
posing. =20

    David Love


      ----- Original Message -----=20
      From: David M. Porritt=20
      To: pianotech@ptg.org=20
      Sent: September 30, 2002 6:01 AM
      Subject: Heavy action


      I have a Baldwin SF-10 here on which I just measured the action =
weight.  C4 is 60 grams down, 45 grams up!  Friction -- obviously is =
good -- down weight bad.  I hate adding lots of lead to the keys, but on =
this piano there are only 3 weights in the bass section, 2 at C4, only 1 =
in the upper treble, and actually 2 in the _back_ of C8.  It appears =
that they did straight pattern leading on this one.  I can add 1 - 2 =
weights to each key and bring it down to 44 at A0, 42 at C4 and 40 at B7 =
(I'd probably just take out a back weight on C8). =20

      There is a point of diminishing returns on some actions where you =
can reduce downweight by adding leads but the additional inertia makes =
it feel to the player as though it is as heavy as it was before.  Does =
anyone think I'd get into inertia problems adding this amount of lead? =20

      dave
_____________________________
David M. Porritt
dporritt@mail.smu.edu
Meadows School of the Arts
Southern Methodist University
Dallas, TX 75275
_____________________________


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