Only a few particular pianos come to mind (over the last 28 years).
The latest is a 1960 about 6'3" Knabe grand on a high school stage (plus it's twin at another high school)
The strings rarely bust during a tuning, but sometime inbetween tunings.
Since January 2006, 3 wound strings have broken, and 12 treble strings, all terminate and break under the de cappo bar, and most in the 2 highest octaves.
The breakage is accelerating. It does get played quite a bit. Mirror inspection of the decappo termination shows a little nitch (which I have been lightly filing at each replacement) and a fairly defined point (as opposed to a more rounded termination point).
I don't know how much the flattened & grooved hammers are contributing. Monies have been tight over the last decade, and maintenance beyond tuning and obvious repairs has been put aside. In the upper two octaves, rounding the flattenened hammers would bring the stike point maybe 1/16" to 1/8" from the inner felt, in-other-words, it would probably be the last shaping the hammers could receive before cutting through the white felt.
Has anyone have a significant improvement in curtailing frequent string breakage with simply hammer shaping/voicing?
I'm sure this beatup instrument is ready for replacement or at least rebuild, but if any of you have already been experiencing a similar story on this era of Aeolian built Knabe, I would appreciate knowing if anything you tried, helped out temporarily, or if nothing worked.
I've also encountered "string busting pianos" that were much younger than this.
An 80s Kimball console,
( 2) 1985 Young Chang grands,
1987 Wurlitzer studio (even my replacements bust within a year or two) ,
and to a lesser degree a couple of older Yamaha consoles.
Any shared experiences appreciated,
Mike, Tucson Arizona
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