String breakage in Seiler pianos

[A440A@aol.com]

Andre writes:

<< Strings usually break because of a malfunction in the action.  A badly 
regulated action causes a pianist to use excessive energy, and a flattened and 
hardened hammer makes it worse.  If you very carefully (and with love) file the 
worn hammers without 

taking off too much, and you then make a beautiful regulation, you will 

notice that less strings will break.

    This hasn't been my experience!  I think strings usually break because of 
metal fatigue, which is the result of repeatedly reaching their plastic 
deformation limit.  This may be a problem with scaling, (% of elastic limit), or 
simply being hit very hard.   I haven't noticed the hammers playing too much of 
a part in it.  Cases in point: 

    We have a Bechstein at the school that breaks a lot of strings.  The 
pianist is a large feller and plays a lot of Rachmaninoff.  I originally thought 
it was because the hammers were hard.  After installing new hammers, (Renner 
Blues), careful regulation,  and voicing it down to a mellowness of some degree, 
the strings continued to break with uninterrupted frequency, (no pun 
intended).  So, I restrung the top two sections.  The strings continued to break at 
the same rate!  
    We have two new Yamaha C2's  in the same room.  One of them is mellower 
than the other, and gets more play.  It breaks strings with regularity under 
the hands of some of the more energetic students.  
    We have a very bright Steinway D that is played constantly. I restrung it 
in 1984 with Mapes wire.  It has never broken a string (20 years and several 
sets of hammers). 
    All in all, I think the breakage is more due to the use or the scaling 
than the hammer's or regulation's condition.  I have a number of other examples 
where strings in pianos with flat hammers don't break as often as some of 
their counterparts.  
    One sure-fire way to break strings is to repeatedly play very fast 
repetitions at FFF.  I think the impact occuring while the string is still 
oscillating from a previous blow may be the culprit, and I think hitting them very hard 
with the pedal down exacerbates the problem.  
Regards, 

Ed Foote RPT 
http://www.uk-piano.org/edfoote/index.html
www.uk-piano.org/edfoote/well_tempered_piano.html