Keybed in Warp Drive

[Larry Fisher]

HI all,

> My conclusion was that the humidity cycle affected the
>keybed causing it to crown toward the floor in summer and return to
>near-flat in winter.  

If the back rail were floating about it would cause the same symptom as
you've mentioned.  As it drops you'd have excessive dip.  As it raises back
up, you'd have less.  All this with no change in the balance rail.  I'd bet
the back of the keybed isn't anchored to the horn on the plate anymore.  I'd
also add a piece of angle iron or square tube ..... 3/4" by 4 feet should do
the trick, spray paint it flat black, run pan head screws through it every 6
inches or so, and mount it just in front of the horns on the underside of
the keybed using PVC-E glue as an additional bond that would also aid in the
elimination of sympathetic vibrations that could occur.  If you're dealing
with a paneled keybed, most likely the glue joints are failed and so
everything is floating all over the place, especially if the horns aren't in
use.

Lar

                                    Larry Fisher RPT
   specialist in players, retrofits, and other complicated stuff
      phone 360-256-2999 or email larryf@pacifier.com
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           Beau Dahnker pianos work best under water