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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