[pianotech] Damper tray block

[Ed Foote]

Jon observes:

>>While you're at it, check the angle of the underlevers. If they are 
too steep, lower the pivot hole.I'll be doing that on an M today. The 
underlevers are pitched downwards so much that there isexcessive 
sliding friction on the key end felts. Fortunately the piano has not 
had a lot of useso there are no trenches plowed outs.I like to have the 
key lift the underlever to being parallel with the keybed at full 
keystroke.This reduces the sliding friction to the minimum, near zero 
at full depression.-- Regards,Jon Page


Greetings,
      It seems that the factory just overlooked the geometry in the 
1960's.  How the engineers of the short Teflon back actions ever 
thought they would work well is beyond me. I also like to make the arcs 
described by key and underlever share some of that magic line thinking. 
I suppose minimal slide would require that the contact point be on the 
magic line at half stroke, but I question whether it makes much 
difference if it hits the line at the end.
       It seems that having the underlever horizontal when at rest would 
apply the maximum weight on the string, and cause the sliding action to 
less than that which occurs when the underlever is sloping down.  I 
don't know that there is room to lower the tray that much in most 
cases, so I also often leave them as Jon mentioned.
    Does anybody smooth the wooden contact point on the underlevers 
with, say, 400 grit paper and a spray of Teflon ?? Maybe, even 
burnished graphite??   Just asking,wondering if there is anybody else 
out there that has run out of things to try........
Regards,

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