[pianotech] Friday puzzler: Won't play on hard blow

[reggaepass at aol.com]

No, they are not at ends of section, and it is not walking hammer center pins.  But wow, the anecdotes about conditions that can cause this failure are really educational.


Alan E.


-----Original Message-----
From: Kent Swafford <kswafford at gmail.com>
To: pianotech <pianotech at ptg.org>
Sent: Fri, Oct 29, 2010 1:56 pm
Subject: Re: [pianotech] Friday puzzler: Won't play on hard blow


Were the 2 offending notes both at the ends of sections? Sometime at the end of a section, a center pin can walk out far enough to leave one side of the flange completely free. The note may play on a regular blow, but on a hard blow the hammer goes off at an angle big enough to completely miss any strings.


Kent




On Oct 29, 2010, at 4:48 PM, reggaepass at aol.com wrote:






This is more fun than I thought it would be.  I've posted this puzzler on both lists and the two groups are at about the same point (if you remove Ed Sutton's formidable contributions from the mix, anyway).  To review for one and all, the instrument in question is a mainstream grand piano of relatively recent vintage.  The answer is neither of the first two things that came to the minds of so many of us, cheating jack and too-close back check (sounds like a country music duo, don't it?).  Nor is it a broken keystick or any of Ed Sutton's deeper speculations (on the CAUT list) about flexing balance rails and broken keybeds (man, Ed, you have seen some pretty interesting stuff!).  Also, it is not Catastrophic Action Failure--remember, it is not a repeated note thing--or a foreign object.


Time for more information:  There are two problem notes, one in the bass and one in the lower treble.  The worse one is in the bass, probably because of the greater mass of the hammer (compared to the other one).  When these notes won't play on a hard blow, one of their neighboring hammers moves slightly.



Going kayaking--back later,


Alan E.
 
 
 
 
 



 
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