Agraff Torque

[reggaepass@aol.com]

Hi Paul,

  Agraffes should be snug, and (in our experience) can be cinched down 
at least 1/4 turn after contact in the interest of proper alignment (to 
a thread running through the corresponding bridge pins). We use both 
the washers and the mill to smooth out the level of the agraffes, in 
the interest of having as consistent a string plane (from unison to 
unison) as possible. Attention to this detail (among many others!) 
helps the action regulate more evenly.

  If you are curious about how much torque an agraffe can take before it 
snaps, slather the threads of an extra one up with lithium grease, spin 
it down to the point of contact, and then continue to gradually turn it 
down....until it breaks. (The lithium grease makes it very easy to get 
the broken agraffe post out of the plate.) If you try this exercise, 
your hands will know what it feels like as an agraffe weakens and when 
it breaks. There ARE many mysteries in life and piano work, but knowing 
when an agraffe is properly seated without going too far needn't be one 
of them.

 Alan Eder, RPT
 California Institute of the Arts

 -----Original Message-----
 From: Dempsey Jr., Paul E <dempsey@marshall.edu>
 To: Pianotech <pianotech@ptg.org>
 Cc: caut@ptg.org
 Sent: Tue, 15 Nov 2005 09:52:36 -0500
 Subject: Agraff Torque

 Lists,

  

  I've had the occasion recently to install new agraffs in a big Baldwin 
I'm rebuilding and a question comes to mind I'd like toss out.

  The agraffs I removed were surprisingly easy to get out. Almost as if 
they were not really tight to start with or perhaps they loosened after 
installation. I guess my question is how tight do these need to be 
torqued down.what's the rule? And, as the thing approaches the 
"appropriate" tightness, and, the alignment is off several degrees, 
which is the better approach..the little washers or using a hollow mill.

  

 Clearly, there is a little gap in my knowledge/skills, agraff wise.

  

 Your wisdom is appreciated.

  

 Thanks

  

 Paul E. Dempsey, RPT

 Piano Technician Sr.

 Marshall University

 Huntington, WV

 304-696-5418

 304-617-1149