Heavy action

[Isaac OLEG]

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David,

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.

  David Love


    ----- Original Message -----
    From: David M. Porritt
    To: pianotech@ptg.org
    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).

    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?

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


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