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Hey Bill
The usual concise & thorough perspective.
Thanks. I can relate to both perspectives & for my uses Johns jig is the
perfect Quick way to confirm residual bearing in his work (or mine) on his board
but I think it will often tell you what the other group needs to know as well
& or just maybe in conjunction with the lowell gauge. Which I think gives
some valid & useful information. The only way to confirm that completley is to
take measurements on a piano one is going to restring & after the strings come
off try to relate them to what is the actual condition of crown ,bridge slope
etc. & then see if you were getting the whole truth. Know what I mean?
I can also confirm residual crown on a my new boards with the bubble type.
Usually .012 to .018. This also squares with a conversation Nick Gravagne & I
had about this very subject.
Now I'll make Johns jig & compare findings & see how they relate.
Regards--Dale
At 9:27 AM -0500 2/24/04, John Hartman wrote:
>In the type of pianos I work on I have never sean a situation where
>a slight tilt to the bridge was found to be the source of a tonal
>problem. It may be a symptom but not the cause. I guess somewhere
>there are pianos with serious bridge role, but expect that by the
>time this develops many other things have gone wrong as well.
With all due respect, John I think this discussion needs a better
answer than that. But with the great admiration and respect I have
for you, I'll also say that from your perspective as a rebuilder,
that this perspective may not provide the answers. The occasion for
concerning ourselves with the three inclinations and in particular,
how the middle one (the bridgetop) may relate to the outside two is
primarily one older pianos of fading resonance. A rebuilder,
especially one who's new soundboard installation greatly outnumbers
his old soundboard repair, would only be looking at the existing
board in an old piano to answer answer the question: pop the old
board out and replace it, or leave it in and repair it.
Given that once a rebuilder's board installation are up and running
(after the learning curve has flattened to the point of allowing
cruising speed), the clear lesson is that it takes far less time to
start from new, rather than work with the old. For that reason, your
position that reading the three inclinations adds nothing to the
decision to replace/repair quite likely already made on the basis of
gross downbearing, is understandable and quite reasonable. For you.
However, David Skolnik and Ed Foote (and others for whom it's
important what the three inclinations can tell about an old board)
are in a different business. Of course, they (oh what the heck, I'll
include myself and say "we") are just as concerned with whether the
old board is going to be the limiting factor in the ultimate
resonance of the piano, as any soundboard installer. And we are
capable of judging whether the limiting factor is action regulation,
a good voicing, maybe a restringing, maybe reinforcing bridgepin
holes and re-notchng during that restringing, or in fact, A NEW
BOARD. However we're a lot further from the "tipping point" of
replacing The board than a board installer is, and not just because
while we might replace a block and recap a bridge, a new board is
something we send out. (That's the matter of convenience.)
The other reason is that the scope of a circumstance in which the
"soundboard question" comes up is usually far narrower, than the
circumstance in which you may be examining a piano for an estimate.
For us, it may be during the first tuning before the owner has
thought to ask us why they have to push so hard in the melody range
of the piano, why the top notes in the bass section are so much
louder than their neighbors to the north. We'd be thinking that to
ourselves as part of our internal monolog, "how can this piano be
more musical". But all this is long before we and the owner are
sitting around the dining room table, adding up the cost of cartage,
hammershanks and the wisdom of partial solutions which won't last as
long as comprehensive "from-new" ones. At this point the owner may
not even know what an action regulation is (or what it costs in
relation to a tuning), and we're already thinking: "I bet those wheat
cracks at the bridge pins in the 5th octave are responsible for the
balance problems, and although a simple crown and bearing checks read
sufficient, I'm going to lay the Lowell on it to find if
epoxy-reinforcing bridgepins will work, or whether what we're dealing
with negative bearing, not between the to the hitchpin/rearduplex,
but between the aggr/capo to the rear bridge pin".
Yep, it's a different business, and if you were in it, you'd probably
be interested in the three inclination too. This said, let me
reaffirm my respect for you and work work.
At 9:27 AM -0500 2/24/04, John Hartman wrote:
>Didn't the photos show it all?
BTW, what they don't show, and what you didn't specify is where along
the speaking length your bearing bars are place. In the photos,
they're placed such that the far end is directly above the duplexes
which is where you want to read your overall bearing. It bothers me a
little that this may make the distance between the far en of the
front flat and the bridge pin, vary. I'm sure that this isn't a
problem in your shop, given the small number of scales you work on.
However I view your bearing check bears as a variation on the simple
three-point rocker gage, with the only differences being 1.)that the
first and the middle points are the long flat front portion, 2.) that
while you use it only to measure gaps at the rear end (*) as Baldwin
does with the Accu-Just system (* go ahead, RicB, I dare you), and
3.) you're placing the middle point in the speaking length with the
front point, instead of on the bridge. But while you might not be
rocking it to get your reading, it's still a rocker gage. As a rocker
gage, it's accuracy depends on how from the beginning of the back
string length the third point hits. Further away, the greater the
reading of the same deflection, and conversely.
Once again, I'm sure it's not a problem in your practise, but for
this peer review group a clarification would be useful.
Finally, I'd like to say that I'm not happy with Tom Lowell's
attention to the market for his downbearing gage, which I believe is
the best reader of what's happened to downbearing and the bridge over
the decades. In fact, some enterprising supply house could look at
his patent to see just how secure it is. I gather that Baldwin's
"prior art" is overwhelming in this little device, and the only
reason he was able to patent and market it was because they chose to
overlook his enterprise. I'd suggest that in light of his neglect
(when's the last time a supply house told you when the item was going
to be back "in stock"), someone else could easily step in, hopefully
with Baldwin's blessings.
Bill Ballard RPT
NH Chapter, P.T.G.
"I gotta go ta woik...."
...........Ian Shoales, Duck's Breath Mystery Theater
+++++++++++++++++++++
Erwins Pianos Restorations
4721 Parker Rd.
Modesto, Ca 95357
209-577-8397
Rebuilt Steinway , Mason &Hamlin Sales
www.Erwinspiano.com
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