YC Strike Weights etc

[David Love]

Just a note of caution.  It is not as simple as just matching the key ratio
on the sharps and naturals.  The key ratio is only one component of the
total leverage of the system.  The others are the wippen and the
shank/flange.  By moving to capstan on sharps to match the naturals (such
that each has an independent line) means that the contact point of the heel
on the capstan will be different.  This means that, though the key ratios
now match, the contribution of the wippen lever will be different.  If you
multiply out the total force leverage, they will still be different.  You
would have to find the position at which the total force leverages are
equal.  That will not be at a position where the key ratios are the same.
Moreover, there is also the distance leverage to consider.  Moving the
capstan on the sharps to give greater mechanical advantage will have a
negative effect on distance leverage, i.e., the hammer won't travel as far
for the same dip.  Since the contribution of each lever is not proportional,
matching the force leverage by moving the capstan, in this case, will not
mean that the distance leverage reacts in the same way.  Neither will you be
able to match force and distance leverages between the sharps and naturals.
You will have to analyze the force and distance leverages to be sure that
creating equality in force leverage doesn't create a problem with distance
leverage and find a compromise that works the best.  It would be easier if
they just put the balance rail pin in the right place.

David Love
----- Original Message -----
From: "Newton Hunt" <nhunt@optonline.net>
To: <pianotech@ptg.org>
Sent: November 05, 2001 7:29 PM
Subject: Re: YC Strike Weights etc


> Think of it like this.  The sharps are not moving the wippens as far as
> the naturals.  By relocating the capstan to match the leverage of the
> naturals the sharps will be doing exactly the same amount of work and
> the naturals.  The touch will then be correct for both keys.
>
> Newton