The Meaning of Key Length

[Farrell]

Something has been bugging me. Key length. I do not play piano beyond a
couple cords. My understanding is that, everything else being equal, the
Steinway D will play/feel better than the Steinway S. The action stack is
pretty much the same on these two instruments (right?), so the only
major/significant difference that might explain the better feel is the key
length.

Key ratios would presumably be similar (keyfront to centerpin
length/centerpin to capstan length), so there would not be an advantage in
leverage. The only thing I can identify would be that for the same 3/8" (or
so) dip in the keystroke there would be less rotational motion in the long
key and more of an arc traveled in the short key. The increased arc in the
short key would perhaps cause more friction at the capstan to wippen cushion
contact point because there would be more front-to-back movement in the
short key compared to the long key because of the increased arc traveled in
the short key.

Is this part of the reason? Is there more? Put your thinking caps on and
explain. Please. Thanks.

Terry Farrell
Piano Tuning & Service
Tampa, Florida
mfarrel2@tampabay.rr.com