[pianotech] Weighing Off A Schafer Grand

erwinspiano at aol.com erwinspiano at aol.com
Sat Jan 30 11:18:41 MST 2010




  Jon
  Now wisdom is speaking. I think we will all be on this learning curve for a while but more things make more sense after a few of these re-engineering exercises
 Nice analysis. Good fix.
  My most recent experience was  a 1976 Aeolian 9 ft Mason & Hamlin with a messy action. 
To start,the key ratio was 1.76 to 1. Not good. 
 Action spread was 4" 5/8 this, never seen this....and the jacks failed miserably to align  with the knuckles. 
  The capstan center was 62 mm from the wippen center, according to many, 66 is optimal. 
 Original Action key ratio approx 6 to 1. Original reg. parameter were 2 inch hammer blow. .370 dip at the pin,2 mm let-off. Too many leads in the keys
 Moving the wippen rail repaired my wippen/knuckle alignment,allowed the capstan a 10 mm move toward the balance rail. I used new wippens with movable capstan heels from Tokiwa.
  This Repaired the 66 mm wippen  mm relationship and moved the overall key ratio to 1.9 to 1. An adequate correction. We removed weight from the keys. Final action key ration was a gratifying 5.5. The regulation is a 46mm blow. 1.5 mm let-off and a .395 dip.  Down weight up weight is like in the very normal range. Balance weight is 39
  The pianist came yesterday. He States "It's beyond my wildest dreams"! It was a good day
 As for the damper system and its replacement...a real night mare. Ask for a tutorial before doing this I think I could help.

   Dale.



Moving the stack is much easier than relocating capstans.
-- 

Regards,

Jon Page

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