[CAUT] String Leveling question

[Fred Sturm]

On Mar 8, 2009, at 4:52 PM, David Skolnik wrote:

> - What, ideally, should bi- and tri-cord level be parallel to?   
> keybed? stretcher? plate?  top of agraffe, (if not rounded, a la  
> Bechstein)?

	In real life, I just try to see if the strings can be level relative  
to the center of the earth, meaning the bubble is centered between the  
lines (most pianos are level enough for this to work just fine - if in  
doubt, put the level on the plate webbing in a few places and see what  
you see). Then the real fine adjustment is that all three strings are  
equally "muted" by the brass, with a subtle pluck of each string. I  
think a lot of people get hung up on some artificial standard of  
perfection, agonizing whether the piano itself is level and so forth.  
That isn't the point of the tool. The point is to get the strings all  
in one plane, ideally parallel with the top of the hammer (must be  
well filed), and at a right angle to the hammer's travel. But minor  
tilting isn't that big an issue - it's far better than the random  
condition it probably was in before. The main point is to have an  
efficient procedure to have the hammer strike all three strings  
simultaneously. If the strings are a bit tilted, you file the hammer a  
bit tilted. If the strings all center the bubble, you will likely have  
a very easy time mating. What you don't want is one string out of sync  
with the other two. So the real test is the even sound of each string  
on pluck, more than where the bubble is.
	If conditions (agraffe drilling in particular) are such that it  
doesn't look like you will be able to get the bubble centered, just  
try to get the strings all in a line to the bottom of the slightly  
tilted gauge. It is possible to overbend the strings. And it is  
possible to get one string so high the others can't reach it (how  
would I know that? <G>) So subtle and discrete pulling is in order.
	BTW, that electronic tool for string leveling that was patented and  
mentioned a month or two ago would use the keybed as the reference. On  
first glance, I thought it was crazy too complicated, but after  
looking at it more closely, I think it is simple and elegant and might  
work quite well.
>
> - How often do you come across ideal?

Pretty often, but certainly not always.
>
> - How many times (at which points) do strings get leveled after  
> stringing?

I like to wait until the piano has been chipped a couple times, and  
like to have it maybe 25 cents sharp, on the theory the bends will  
migrate as the wire stretches (so they should be at a "sharp" point in  
the wire), and making the bends will drop the pitch. That is to say,  
after bending I expect the pitch to be a bit sharp still, but I expect  
it to drop more or less to pitch over the next week or so, and then  
the bends will be more or less where they ought to be. I do a rough  
leveling then, not being overly particular. Then I do a fine leveling  
some time later before voicing. Over the lifetime of the stringing,  
there may be touch up of a few strings any time you voice.
	BTW, I have read on this list a lot of fussing about whether the tool  
is at the strike point. In my observations over the last few months,  
in most pianos it is possible to place the level either right at the  
strike point, or a mere centimeter or so in front of it for most  
unisons. So this is really a non-issue in most cases.


Regards,
Fred Sturm
University of New Mexico
fssturm at unm.edu