[pianotech] Weighing Off A Schafer Grand

[wimblees at aol.com]

Jon

Perhaps a combination of the two will make enough of difference to satisfy the customer. 

What you're proposing, although very impressive and I am sure got the results you were after, is what I would consider a major reconfiguration of the action, which might be justified on a top quality grand, but not on an the piano Patrick has. 

Perhaps it is the only solution for this piano, but it is just not worth it. The customer would be better off buying another piano. 


Just my 2 cents worth

Wim



-----Original Message-----
From: Jon Page <jonpage at comcast.net>
To: pianotech at ptg.org
Sent: Sat, Jan 30, 2010 2:50 am
Subject: Re: [pianotech] Weighing Off A Schafer Grand


Moving the wippen rail will have marginal effect on BW. Check into relocating
the entire stack back. If there is ample room between the keys and the keyslip,
there is the option to move the stack back and the whole action forwards to
maintain the strike point.


A few years ago, I had to remanufacture an action which involved lightening the
hammers, moving the knuckle, moving the stack and removing lead. The problem
was a heavy action with excessive after touch.


Here's the results on middle C:


a. original survey
b. Reshape hammers/taper/re-arc tails, graduate weight
c. move knuckles out 1mm on shank to 18.5mm
d. move stack back 3mm
e. alter FW to target 38 BW

Survey of C4
    UW  DW  BW  F   SW   FW  SBR
a  32   60    46  14  10.9  32    6.4
b  26   52    39  13    9.9  32    6.3
c  24   44    34  10    9.9  32    5.8
d  22   38    30   8     9.9  32    5.4
e  30   46    38   8     9.9  24    5.4


Even after relocating the knuckle further from the center pin, the jack was still
being buried into the stop cushion. So in order to maintain a 10 mm key dip,
I relocated the stack. KR was in a nominal range and did not require alteration.
Moving the stack is much easier than relocating capstans.
-- 

Regards,

Jon Page

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