Touchweight Key Ratio Question

[David Love]

I would just measure with the coiled weight sitting directly on top of the
capstan since that is the point at which the wippen will make contact.  The
effective ratio will be a function of where the capstan enters the key
anyway.  If you want to compare, take the capstan out after taking the
measurement using the coil method and set a 10gram weight directly over the
hole and see what happens.

David Love

----- Original Message -----
From: "Farrell" <mfarrel2@tampabay.rr.com>
To: <pianotech@ptg.org>
Sent: January 05, 2003 3:40 PM
Subject: Touchweight Key Ratio Question


I am doing preliminary touchweight measurements on a 1902 Knabe grand. The
capstans are angled back at a fairly steep angle (30+ degrees?). They are
also tall, a good inch or so. When making key ratio weight measurements you
are supposed to put a 10 gram weight around the capstan and measure. On many
actions, the weight drops down to the key and is reasonably centered around
the capstan contact point with the wippen. On this capstan, because of its
steep angle and height, when the weight (three coils of hammer lead) is a
fair bit towards the key front from the capstan top. I suspect I should be
centering the weight on a perpendicular from the key directly below the
capstan contact point. Is this correct? In this case, the weight center will
have to move toward the key rear from where the capstan screws into the key.
Thanks.

Whew. A lot to this piano stuff.

Terry Farrell

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