[CAUT] left to right or R to L?

[Fred Sturm]

On Nov 13, 2008, at 8:48 AM, Jeff Farris wrote:

> I have seen several Steinway pianos with the bottom of the strut  
> filed at
> the point where it crosses the bridge (and also at the curved area  
> inside
> the "cut out" for the bass end of the bass bridge) to prevent  
> rubbing. Was
> that "planned"?


	That could well be variation in casting. Blame Kelly <G>. At least  
until S&S bought them a few years back. Since when the quality of  
plates - agraffe spacing etc - has improved a great deal.
	Measuring the two Steinway grands I tuned this morning (and old A and  
an old M) I found clearance between strut and bridge top ranging from  
8 mm treble to well over 15 mm tenor. Obviously this is under load and  
old, flat boards. Don't know where the board/bridge would have been  
when new and at top humidity. How much lowering of a bridge under  
string load is considered a "normal" range? I guess you have to  
specify at what RH/EMC.
	A second question would be how much will a soundboard not under load,  
but glued to a reasonably solid rim, move up and down (measured at  
bridge top in various locations) between, say, equilibrium at 10% RH  
and at 90% RH?

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