Action Balancing/Leverage Quagmire

[David Love]

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Of course, a smooth FW system is patented by David Stanwood.  With =
varying
KR's you will have to choose between uniform BW and smooth FW.  =
Personally,
I would opt for uniform BW.  Others may disagree.  Of course, you can do =
a
varied capstan line, one for sharps one for naturals since your =
different
KRs are divided that way.  That way you can achieve a relatively uniform =
R
and then the degree to which your FWs are smooth will depend on how =
accurate
you are with SWs and inherent irregularities in balance rail line and =
other
things.  The way around that is to use an assist spring wippen (more =
$$$).
Depends on how much you and they want to get into it.  The sharps and
naturals feel differently enough anyway due to their difference in =
overall
length that a small variation in BW or FW between the two will probably =
not
be noticed.  Anything you do along these lines will be enough of an
improvement that they will probably buy you the beer. =20

=20

David Love
davidlovepianos@comcast.net=20

-----Original Message-----
From: pianotech-bounces@ptg.org [mailto:pianotech-bounces@ptg.org] On =
Behalf
Of Farrell
Sent: Thursday, August 04, 2005 6:01 PM
To: Pianotech
Subject: Re: Action Balancing/Leverage Quagmire

=20

Thanks for the input David. Comments interspersed:

=20

With a .55 key ratio you definitely need a 17 mm knuckle, probably an 18 =
mm
but they don't make them.  Ideal  situation would be if the action would
accommodate a capstan move to .52  with a knuckle at 17 mm.  Variations =
in
the leading and balance weight with a non conforming SW curve accounts =
for
the range of BWs through the action.  Friction range is too great.  =
Check
the key easing on the high ones and remeasure balance weights to see if
that's the problem.  Remeasure the bore distance (string height to =
flange
center) and see if the hammers are bored correctly.  Improper checking =
might
be due to improper tailing or incorrect backcheck angle.=20

=20

Haven't checked where all the friction is coming from - but sure, we =
need to
do that. And that's what I was getting at when I stated crappy hammers.
Hammers (they are new) overstrike, and are bored at an angle so that the
nearly squared-off tails stick outward to the rear - these things will =
never
check as is unless maybe you put some bubble gum on each backcheck. The
action needs new hammers, bored properly with tails arced properly.=20

=20

Best fix: =20

=20

1.      Remeasure hammer bore dimension and either replace the hammers =
or,
after removing from original shanks,  plug and redrill if they are wrong =
(a
little tricky when they are already tailed, but can be done. (4 hours)=20

2.      =20

Yup. Would like to just replace.

1.      Dry fit onto new 17 mm shanks and smooth strike weights using a
table saw for clean tapering.  Retail to correct radius.  With .55 key =
ratio
you will need SWs on the lighter side.  Do some samples and determine if
your curve will allow you to move the FWs back down below maximums.  If =
you
are unable to get the hammers light enough to bring the BWs down with
reasonable FWs, experiment with a capstan move to .52 or as far as you =
can
without going off the cushion.  Double check your new BW/FW relationship
with some samples. (4-8 hours)=20

=20

Sounds good!=20

=20

So you would recommend consistent BWs across the keyboard over smooth =
FWs
(if I am reading you correctly), i.e. sacrifice perfectly smooth FWs to
achieve consistent BWs?

1.      Install new hammers. (3 hours)=20

=20

Would love to.

1.      Bench regulate and address friction areas checking keys and =
pinning.
Include check of backcheck angle and/or new leather. (4-6 hours).=20

2.      Reweigh action by charting BW for each note and then remove lead =
at
1:1 ratio (1 gram off FW reduces BW by 1 gram) to achieve desired BW.  =
(4
hours)=20

3.      Take to customer and do final reglation, tuning and voicing in
piano. (4 hours)=20

4.      Give bill (estimate 22 - 28 hours plus pick up and delivery, =
plus
shanks, plus new capstans if needed-add 3 hours and a new set of hammers =
if
new hammers are in order) collect money go home and drink beer.  Your
mileage may vary.=20

=20

David Love
davidlovepianos@comcast.net=20

=20

Thanks for your input. Phil? - time to put your salesman's hat on!

=20

Terry Farrell


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