more heresy

[Richard Moody]

----------
> From: Stephen Birkett <birketts@wright.aps.uoguelph.ca>
> To: pianotech@ptg.org
> Subject: Re: more heresy
> Date: Tuesday, August 19, 1997 2:57 AM
> 
> 
> I have plenty of data on crowning and downbearing in early pianos.
If
> someone would care to supply some data on modern pianos, I would
gladly
> undertake to compare these two. The discussion that has been taking
place
> here has condensed down to just that one question
really...precisely how
> do downbearing forces and non-loaded crowns compare?

But what data could there be? Take an experience we (this forum) have
most in common, restringing the modern piano. (After say 1880)  What
data do we gather, or better what data can we gather? 
The scale is the main source of data which is the easiest to record.
Down bearing is next and most of that is taken with the three legged
device.  All that really does is indicate that there is some down
bearing.  As to how much, how could it be translated into data?. So
anyway we rock the device on the bridges and say there is or isn't
much "down bearing".  Then the string tension is released, the sound
board after all those years of perhaps 2,000 lbs of down pressure
from the strings is suddenly unburdened.  It raises up a little bit. 
Do we measure this "upraise"  Well Travis describes a way to do it
with slanted (tapered) sticks inserted between the sb and the plate. 
But what if the plate rises (or falls??) because of the release of
tension? Do we attempt to measure that? 
	So  the bare soundboard (with its bridges) sits there awaiting new
strings. Now where does crown come in?  And is it (or can it be)
measured, if so, how and when? Before the strings are put back on,  a
fabric string is run across the bridge from the agrafs to the 
hitchpin to determine what bearing is to be expected.  Then the
strings are put on and pulled to tension.  The sound board goes down.
 To complicate matters, among at least 100 considerations, (probably
more like 1000) the soundboard can be thicker and thinner in places,
the string tension can be uneven, yet the bearing then should be set
and set accordingly or so it would seem.  But who can say what is
"accordingly"?  Well Travis says dime, nickel, quarter, in treble,
tenor and bass; can we really get more emperical than that?  At least
it is a guide line.  But then there is front and rear bearing across
the bridge. Oh,, and did  you look at the shape of the grooves across
the bridge after the strings were removed.  Does this give any
information as to how the strings were, and consequently how they
(the new ones) will be seating on the bridge? Can you call this
information data? 
	Ok there is emperical (measured) knowledge, and experience (what's
the better word?)knowledge. I would think one would have to use each
as much as possible, when building or rebuilding any musical
instrument. 
> 
> And I don't think *all* old methods are best..... Seriously, I am
only 
> suggesting that you modern guys and gals learn the old ways the way
they 
> *really* were, rather than how we were always told they were, 

> Stephen

Good suggestion, but how can we *really* do that??  ie whose
knowledge (method) is/was better than what "we were always told"? or
better yet who can tell us, since the good "old ways the way they
really were", were done by those who have gone before us?    

Richard