Fortepiano Touchweight

[PSLOANE@OCVAXA.CC.OBERLIN.EDU]

                         --   ORIGINAL POSTING AND REPLY --

>How is touchweight dealt with when building fortepianos?
>
>Stanwood

The actions I have built were Viennese style kit actions from Zuckerman.  I
have not examined a lot of original pianos to see how they are set-up in
this regard.  On the Zuckerman the keys are leaded at the rear (with a
single weight) in order to increase the downweight at the playing end to 15
grams. Pretty light!

I have a mechanical drawing of the action from a Cristofori piano from the
Leipzig University collection (push action) on my wall and it shows no
provision for key leads.  I will ask my friend David Sutherland who is
building one based on this design what he has seen in this regard (and what
he plans to do with his) and let you know.

Bill Darst, RPT
Music Dept
UC Santa Barbara

                                   -- MY REPLY --

The following are vague recollections from a conversation with fortepiano
builder, Richard Hester:

I'm not certain of this, but I think the introduction of weights in forte piano
keys was done to facilitate key return, hence the appearance of weights in the
rear of the keys in Bill Darst's Zuckerman kits. Richard Hester, fortepiano
builder, however, claims that the proper way to facilitate key return -- by
modifying the key, i.e. -- is to shave mass off the key at the front. Obviously
this needs to be done on the bottom of the key and should also be done as far to
the front as possible to gain the most from the mass taken off. This not only
reduces the weight necessary at the back of the key to push the key back up, it
also reduces inertia in the key as opposed to the increase in inertia that
adding a weight at the rear produces. Reducing inertia allows the key to
accelerate/decelerate more quickly and helps provide more responsive key
movement and repetition for the piano in general. Richard Hester did this to the
fortepiano he built for our school (Graff replica, Viennese style action) to
solve a repetition problem, and it worked wonderfully. As I recall, he said this
was a "standard" building practice (as oposed to using weights???). Maybe those
old builders knew more about things like inertia than we give them credit for.

Ken Sloane, Oberlin Conservatory