[pianotech] Petrof breakng strings

[Joseph Garrett]

From: Mike Spalding <mike.spalding1 at frontier.com>
Mike said: "To: Pianotech <pianotech at ptg.org>
Subject: [pianotech] petrof grand breaking strings
Message-ID: <4E67DE17.4020606 at frontier.com>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
 
A non-computerized colleague has asked me to post this question: A 
3-year old Petrof grand, 5' 8", is experiencing string breakage in the 
capo section, which in this piano extends from the top of the agraffed 
tenor all the way to note 88. It is played several hours per day by a 
gifted 12-year-old boy. He is normal size for his age. The tech has 
filed hammers and increased let-off, but it continues to break strings. 
He has considered rounding off the v-bar, which he has observed (with a 
mirror) to be quite narrow and sharp. Question: is this model 
particularly prone to breaking strings? How would you attack this problem?
 
thanks,"

Mike,
I would first take the scale and evaluate the tension/breaking strength
situation. Once I did that I'd probably re-contour the Capo Bar and smooth
it. If that didn't take care of it, I'd just restring the areas in
question. As for the regulation, I've found that if the piano is in good
regulation and the hammers are properly surfaced, (er......"shaped"...hate
that term!), to the proper contact shape, The breaking string problem goes
away. Exceptions to that are Southern Baptist Situations w/o a proper
Monitor for the pianist. I'd also ask what kind of music is being played
and ask when the last time the musician had a hearing evaluation.<G>
That's my take on that.
Joe


Joe Garrett, R.P.T.
Captain of the Tool Police
Squares R I