Bill:
Thanks for your comments. Just a comment briefly, I wasn't trying to
suggest that high strike weights were a necessary part of the design, just
what I observe as a preference. Though each installer, as you mentioned,
can presumably request that designs follow their own specifications, it is
my assumption, from limited observation, that Stanwood installers are
following his design preferences. I could well be wrong about that.
It seems reasonable to assume that the past use of assist springs did not
approach the current applications of smoothing balance weights. However, it
is seems not unreasonable to assume that they were used to help create lower
inertia actions. Limiting the use of the springs to carry only the weight
of the wippen is, I think, not a bad idea. Though I have no research to
back my intuition in this, I am inclined to think that anything that causes
separation of the wippen from the key can't be a good thing. This idea
seems to be loosely supported by the number of people who gasped at the
thought of my changing an old Bechstein rocker arm action to a more modern
capstan system. The consensus seemed to be that the old system performed
better. If it does, then it seems that the connection to the key is key, as
it were. With respect to the wippen-key connection, the assist spring's
function is exactly opposite.
Following the action design discussions for the past few years along with
individuals' expressed concerns, I observe that inertia has become sort of a
dirty word--something to be avoided or minimized at all costs. There is no
question that when encountering action after action that throws 6-7 leads in
each key to compensate for a mismatch of strike weights to action ratios
that this needed to become a area of focus and David Stanwood should be
credited with making this part of the everyday dialogue. But now that we
have turned our focus that way and explored the lower limits, I am finding
that the actions that are appealing to me and to my customers are measuring,
not surprisingly, somewhere in the middle: not enough to fight you, but
enough that you can easily feel what is going on out at the end of the
system of levers. While new protocols for creating eveness through the
action are always welcome, it seems quite possible that jumping through
hoops to lower inertia can be counterproductive.
What I am beginning to think is that the original designs with slightly
higher action ratios (6.0 - 6.1) delivered something that the more modern
trend of 5.5 or lower cannot, that there is something inherent in the
relationship between key and hammer movement that is critical in imparting a
sense of control. While this necessitates relatively low strike weights (by
today's standards), I am more and more inclined to think that this dilemma
represents the Sophie's choice of action design.
David Love
ite that or the things I mentioned (assist springs,
----- Original Message -----
From: "Bill Ballard" <yardbird@pop.vermontel.net>
To: "Pianotech" <pianotech@ptg.org>
Sent: October 30, 2002 8:25 AM
Subject: Re: Fw: Patent Notice
Thank you, David, for a very clear statement of the patent issues
here. (No, I haven't taken the time, as you did, to actually read the
document.)
At 10:41 PM -0800 10/29/02, David Love wrote:
>But this discussion can also serve as a vehicle for differentiating between
>Stanwood methodology and Stanwood design.
Do I understand correctly that the former is that which he has placed
in the public domain (and which is included in the PianoTek) kit),
and the latter is a set of specifications for an individual action
resulting from his current procedures and thinking, most of which
would be on the other side of the proprietary line from the former?
At 10:41 PM -0800 10/29/02, David Love wrote:
>Some of the aspects of what I observe are
>the characteristics of "Stanwood design" are clearly neither new nor
>proprietary: the tendency toward high strike weight zones, the use of
assist
>springs to reduce front weights, the placement key leads toward the balance
>rail.
(I'm not sure I can speak for David, but a fool rushes in.) By "the
tendency toward high strike weight zones", do you mean his preference
for heavier hammers and the possible influence this personal
preference might have had on the location of SW guidelines? When a
certified installer sends that action's raw specs for the action (new
parts without correction), the installer can request that SWs stay
within certain bounds (or even specify his own at the outset). If
the installer is generating his own design, based on the full breadth
of David's procedures, he is in control of SWs. I wouldn't call
David's inclination towards higher SWs (if that's what you had in
mind), a necessary part of Stanwood design.
"The use of assist springs to reduce front weights"? You're probably
referring to the long years in which these were installed in European
(and some Asian) pianos. Was there ever a procedure for the setting
of the strength of these springs, any more involved in than simply
removing the weight of the rep? (ie. strengthen the spring until the
rep hover in mid-swing?) That's kind of like inventing a rail with 88
let-off buttons, choosing the button thickness to set the let-off in
some general neighborhood well short of the string height (a generous
safety factor of 1/4"), and as a finishing touch (taking advantage of
the fact that these buttons turn), setting all screw eyes parallel to
the rail.
Of course, I haven't done extensive studies of these actions
(Steinways, Bosedorfers, Bechsteins, Schimmels, Kawais, and Baldwin
Howards among them) to see whether the FWs accompanying these helper
springs showed any sign of being set in anything more focused than
just an across the board 10g reduction. (David has.)
Most of these factories no longer use the helper spring, and the
standard explanation is that helper springs complicate deep fast
repetition. This explanation as far as I've noticed is anecdotal,
speculative, and not backed up by engineering studies. I'd be willing
to bet that the helper spring got dropped because the limited use
which the factories were making of them didn't justify their extra
cost to the manufacturing. I don't have the Renner USA booklet on the
appropriate use and installation, but I remember it being vague on
both mattes. Presumably Lloyd Meyer got the best of the Renner
factory's wisdom on this style of rep when he engaged them to produce
helper spring reps. I don't remember the booklet showing much sign of
that wisdom. Renner of course was around for those long decades of
intermittent factory use of these reps (and frequently supplied them
to the factories).
To return to the let-off rail analogy, certainly if l-o rails had
been on the scene (albeit, with their poorly understood use), someone
who discovers that the buttons can be turned to set in a uniform 2mm
escapement can't claim to have invented the rail and buttons. But by
the same token, the rail and buttons in their current use would not
be not much to take credit for, without the discovery of their true
capability.
Finally, "the placement of key leads toward the balance rail" is
certainly not appearing for the first time in David's work, nor am I
aware that he has claimed so. This is a simple engineering issue,
decided on considerations outside of David's methodology.
At 10:41 PM -0800 10/29/02, David Love wrote:
>I don't mean this as anything but a compliment, but I
>sometimes think that David Stanwood owes his career to the inability of
>manufacturers (read Steinway) to follow the original design.
As might anyone of us devoting a major chunk of heir career figuring
out how to correct a badly hung action.
>Is that because they didn't have the information? Or were they just
>not paying
>attention. It's something I'll have to look into...... someday.
I think this answer is unknowable for many reasons, and hence
speculative. What can be read is the record of FWs left by each
manufacturer in each piano. If all one knows about is DW (and maybe
UW), one wouldn't be drawn into the study of FWs. Thank you David,
for getting us started in exploring what of David's ideas may have
already appeared in the collective thinking of piano technicians.
Bill Ballard RPT
NH Chapter, P.T.G.
"We mustn't underestimate our power of teamwork."
...........Bob Davis RPT, pianotech '97
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