Petrof Quality

[Dean May]

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Hi Dale,
 
So why don't you take weight out of the hammers by arcing the tails and
trimming the sides? 
 
Dean
Dean May             cell 812.239.3359
PianoRebuilders.com   812.235.5272
Terre Haute IN  47802
 
-----Original Message-----
From: pianotech-bounces@ptg.org [mailto:pianotech-bounces@ptg.org] On
Behalf Of Erwinspiano@aol.com
Sent: Thursday, December 08, 2005 6:41 PM
To: pianotech@ptg.org
Subject: Petrof Quality
 
  Listers
   After a recent encounter with a 10 year old 6 ft. Petrof ,my once
fairly high opinion of them has sunk. I generally have liked the sound
of there bellies & the workamnship looked good but  I had the following
experience.
  The action although upon examination had a nicely done 5.3 overall
action ration the touch was extremely heavy high 60's down & below 20
up. The problem is that the hammers were just way to heavy for example
Note 16 was 10.5 grams. That's  hammer wt. not strike weight.
  So extrapolate those heavier than normal readings thru the rest of the
scale.
  Since the desired service was to make it play more like a Saturn than
a truck  & no parts were being changed the original parts were used. The
remdey was to  add one lead to a sparsely leaded keyboard  & then adjust
the wippen springs. Even at that the average down up weight was around
56 to 22 up which is a 39 balance weight.
 I believe  the real solution was a lighter set of hammers & subsequent
even leading applied with springs detached to some higher than normal
nominal number down/up numbers & then re -tweaking the springs. for a
light bit of wippen weight removal from the system.
  This to me was a prime example of a nicely done leverage set up that
was doomed from the git go due to extreme hammer weights It seems  all
grand piano actions fall within certain reasonable & typical leverages
that when exceeded are problematic until rectified by appropriate
counter measures.

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