Allen, and List,
I do apologize for recent laecunae (read: "large, gaping holes")
in logic, correspondence, thinking, memory, etc.
As briefly as possible, my mother was diagnosed with terminal cancer
last April, died in Sept., and my father simply went around
the bend. I've been handling all of their affairs for nearly a year now,
and have just returned from moving him to a nursing home in
South Dakota, where one sister-in-law (bless the dear lady)
is a geriatric RN.
So, the net effect is that I have not been my normally
acerbic, curmudgeonly self for a bit; and I seem to have left
a very great deal undone, finished, etc. We all go through times
like this, it's just a question of when. For me, it's been a real
chance to spend some (more) time figuring out (as Peter Sellers
once said) "whoever the hell it is I am"...
Moving right along to issues at hand, the 1.5 degrees is not pulled
out of thin air. The gist of the numerous journal articles, etc., is that
1-1.5 degrees of deflection provides reasonable bearing on a board
with reasonable crown. Del has written extensively on the analysis
of this, and Allan Vincent had a publication out (while he was at
Baldwin) that was a more concise version.
In the specific instance of a 1976 D, the main reason I suggested
looking to this area is that Ds in general _seem_ to have a
tendency to have various kinds of crown/bearing problems as
they age. Clearly, if they don't go together properly to begin
with, there isn't much that one can do except to make the
instrument a comfortable as possible, and hope that no one
notices any obnoxious weaknesses. It is not at all unusual
for a 20+ year old D to have very crown left (in some, often
illdefined, and non-regular areas). In such cases, excess bearing
(often in concert with things like: poor strike point, boring,
action geometry, hammer condition), will choke off any potential
the instrument may have.
There is a good deal to check out here, and a very good exercise
would be to take advantage of looking at each possible (reasonably
major) source of trouble, make judicious changes (one at a time,
if possible), and then stop to evaluate what had changed, and
then plan what to do next.
Much of the outcome has to do with how much time the
individual technician is willing to donate to a particular cause. We
all do this; and we must be careful to pick which instruments
"deserve" this largely uncompensated activity.
My "normal" course, on instruments that I have not seen before,
is, most often, to spend time with the instrument, tune it (if at
all possible), do a fair amount of reductive measurement of
the action, crown, bearing, etc.. Then, perhaps after lunch, or,
at least, a coffee break to allow my own process to work, decide
on possible courses of action. Some of the possible fixes
obviously will require more time/materials than others, so, as the
technician, you must decide what will be the most effective
and efficient use of your time - most often, unfortunately, this
is tightly regulated by the owner's budget. Since so many
pianos (nowdays) exist in environments where the owner's concept
of tone is limited to the nonsense which passes for recorded piano
sound today, you may be limited to simply hardening the hammers
past all reason, and then ruining them by crown-needling in order
to mask the nasties. If that were not to be the case, then other
opportunities open up.
In the instant case, (NOTE: the following is suggested as a
possbility _only_, and is not intended as a cure-all) I'd first
off take a _very_ close look at the crown on the board. It
would not be surprising to find that there exists little to no,
or, perhaps even negative bearing from the high tenor up. At
the very least, things will not be "regular" (which is to say, even)
from one section to the next. Depending on how much crown
is found in what area, and based on what I remember of the original
post, I think I would probably modify the bearing so that it was
1 degree (nominal) beginning with the first treble and running
to the top. Depending on how old the strings are, I'd also
restring the top two sections, CA gluing or epoxying the
bridge pins, and retooling the Capo as I went. This can be
safely done, a full section at a time (if the plate is in good shape)
without lowering the overall tension on the piano.
Depending on the state of the crown, and since the subject instrument
is an S&S and not a Rippen, we can assume that it should have
positive and not negative bearing. This means that you can shim
or grind the aliquots as necessary (within reason) to achieve that
1 degree. Grinding is best done on a floor mounted belt grinder,
if one does not have access to machine tools. I've shimmed the
aliquots with various materials over the years, and have would up
feeling the most pleased with a combination of fiber board (like that
which used to be used under the back rail felt), brass and aluminum
shim stock. The metal is, to my ear, preferable, as it transfers
more energy to the plate. If you have to shim the aliquots very much
it's a good idea to drill through them and into the plate before starting
so that your shim stack doesn't slide all over. Lowering the tension
on one unison at each end of each aliquot will allow you to drill under-
neath where a string goes, and will be more aesthetically pleasing.
It's possible, and the situation occasionally warrants, that one become
massively anal about this. In that kind of case, one can even
experiment with different "settings" by hand (as it were). My experience
with that kind of approach is that if I have done the procedure outlined
previously, I then get better results by going back to the action, and
rechecking things, starting with the strike point. What worked with
one set of bearings may not work as well with another. This is especially
true if one is dealing with one of the pianos which seem to have been
assembled by Cummins diesel mechanics, with the plate bolts tightened
down to 200 ft. lbs. (Just joking, but only sort of...one result of this
kind of over tightening is that one winds up with, sometimes, 5-6
degrees of bearing.)
Oh, by the way, while working on the bridges, do remember to check and
be sure that some well-meaning colleague, in a fit of over-exuberance,
did not, in "seating" the strings, drive them half-way to China. If that has
happened, ....
Hmm. Guess I should have mentioned that earlier. Like I said, not
quite running on all 8 just now.
Does this help? Sorry, I don't "do" much abstract theory these days,
I am glad to dig it out and go through it, but would certainly to bow Del,
or any of the others on the list who have these things more immediately
under their fingers.
Best.
Horace
At 05:06 PM 1/27/98 -0500, you wrote:
>Horace: you wrote recently (I have excerpted with a machete!)
>
>{{ Idle thoughts from a currently swampy mind. Horace }}
>
>The gist of your commentary it was some very good suggestions about
>considering other possible problems with the "D" under discussion, including
>restringing frequently (the treble esp.)...
>
>You're next posting was brief because you were heading out the door, but
>mentioned something about the 1.5 degrees of deflection of strings off the
>bridge as possibly being an issue. Any chance you could elaborate? And thanks
>for your previous comments.
>
>Allen Wright
>
>
>
>
>
>
Horace Greeley
Systems Analyst/Engineer
Controller's Office
Stanford University
email: hgreeley@leland.stanford.edu
voice mail: 650.725.9062
fax: 650.725.8014
This PTG archive page provided courtesy of Moy Piano Service, LLC