Yamaha CF Regulation specs

[David Nereson]

These spec's are supposedly for all Yamaha grands (from handouts at Little Red Schoolhouse):

keyboard front bushing           0.3 mm lateral movement
keyboard center bushing        0.1 - 0.2 (mm, I presume) lateral movement
white key height                    64 mm from keybed to underside of key covering
black key height                    12 mm above white key
key dip                                 10 mm
repetition lever height            0.2 mm above jack
hammer to string                    48 mm
let-off                                     3 mm in bass graduating to 1.5 mm in treble
drop                                       let-off plus 2mm (i.e., 2 mm below point of let-off)
back check                            15 mm (from string)
keystop rail                            1 mm above black key
damper lift:                damper should start to rise when hammer has traveled 1/2 distance to string
damper pedal stop:   dampers should stop at same height either by key or by pedal
damper stop rail:        1 mm of damper head when lifted above position raised by black key with hard blow
shift pedal:   hammer should move an amount equal to the distance which separates the center lines of 2 adjoining strings of a 3-string unison

[How one measures 0.1, 0.2, or 0.3 mm of lateral play in a key bushing, I don't know -- maybe with a dial micrometer indicator.  Same with the rep. lever height above the jack -- you just learn it by feel, or by "winking" the jacks when the hammers are at rest.  And the spec for the una corda pedal (shift pedal) is awfully scientific -- no consideration for voicing mentioned.]  

    --David Nereson, RPT                                   

  ----- Original Message ----- 
  From: PianoTek4u at aol.com 
  To: pianotech at ptg.org 
  Sent: Monday, July 14, 2008 6:39 PM
  Subject: Yamaha CF Regulation specs


  Dear Colleagues:

  I seem to have misplaced my sheet on regulation specifications for a Yamaha CF.  Anyone happen to have them handy?  

  Many thanks in advance.

  Tony Bajada





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