Action Geometry - Help

Avery Todd ATodd@UH.EDU
Tue, 03 Sep 1996 20:31:34 -0500


List,
   I hope I can explain this clearly enough for you to understand. I'm having
a problem with this Marshall & Wendell grand I'm working on. I've installed
new hammers and shanks on the old flanges, new let-off button felt, new
backchecks and new front & center rail felt.
   I've duplicated the old key height on notes #1 & #88 (on the bench), and
set approximately the same hammer blow and let off on each end. I can get
the #1 hammer to go the full dip, etc. Everything seems like it will work out
fine. However, on #88 I can't get the key to quite go the full dip even though
I can get app. the same let-off and drop as on #1. It won't go into check
because the jack jams into the cushion felt preventing full key travel. The
paper & card FR punchings are still what was there originally.
   The only thing I can find that "might" be wrong is the action spread is
4-9/16 on #1 and 4-5/8 on #88. Could the wippen rail being that 1/16 inch
further out cause the problem with the jack jamming into the felt? I've
never had to do any changing of the action spread before and I want to make
sure I'm not opening up a can of worms here.
   I still need to take the action to the piano to determine the best key
height and hammer blow, etc. but wanted to at least get everything working
approximately before I do. Maybe when I get to the piano I'll be able to
see some other difference, but right now I can't think of what it would be.

   Any help would be GREATLY appreciated.

Avery

_____________________________________
Avery Todd, RPT
Moores School of Music
University of Houston
Houston, TX 77204-4893
713-743-3226
atodd@uh.edu
_____________________________________






This PTG archive page provided courtesy of Moy Piano Service, LLC