upright hammer bore angle

[Gene Nelson]

Just recently worked on an old upright with similar problem.
The original hammers were tapered on both shoulders to avoid interfering with neighbors.
The manufacturer was trying to match the hammer angle to the bass string angle.
I boared the new ones at 6 degrees and was able to avoid tapering. A few trials at 7 through 20 degrees would cause interference problems. The new hammers were a bit larger than the originals.
I did not see the need to attempt to match hammer/string angle.
Gene
  ----- Original Message ----- 
  From: Dave McKibben 
  To: Pianotech 
  Sent: Saturday, December 16, 2006 7:53 AM
  Subject: upright hammer bore angle



  Hello all:

  Could someone explain, or lead to a book that explains how to figure out hammer bore angle on an upright piano.  I have an issue going on with regard to new hammers on an upright but the whole bass section does not work.  They interfere with each other before the hammer gets to the strings.  I suspect it has to do with shaft length, hammer blow distance and other measurements, but as you can see, I just don't know the details.  The problem is.........its always the details that mess ya  up :)

  Thanks much

  DavesPianotuning at earthlink.net
  http://www.home.earthlink.net/~davespianotuning/
  858-776-2516

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