[pianotech] Upright Key Weighting

[Joseph Garrett]

Floyd said: 

"From: "Floyd Gadd" <fg at floydgadd.com>
To: <pianotech at ptg.org>
Subject: [pianotech] Upright Key Weighting
Message-ID: <39BD3CBB602240DA8A1EA5935DF1FF1E at evo>
Content-Type: text/plain; charset="iso-8859-1"
 
List,
 
I have a client (a piano teacher) with a 1906 Heintzman upright piano. She
is concerned that the touch feels too light--that there is too big a
distance between what her students encounter on this piano and what they
will find when they play in festival or in an exam.
 
First, an assumption. Let's assume that the "preferred" pianos against
which this is being compared are not just badly weighted and regulated
grands; let's assume the the comparison is against a well set-up grand.
 
The Heintzmans of this era tend to be well designed and set up. This piano
behaves pretty much like any of its contemporaries in good playing
condition. Friction and wear are not significant contributors to the
complaint.
 
My experience in altering the key weighting of verticals has been focused
on small pianos from the 1960's. Following a post in this forum by Stephen
Schnell (November 18th, 1996) in a thread called "Small vertical key flop",
I have been backweighting keys for an upweight (with hammer held out of the
way) of 15 grams, then adjusting the hammer return spring to achieve a
downweight of 50 grams, or thereabouts. Add to this the normalization of
friction throughout and thorough regulation (especially damper timing) and
I end up with a much improved piano. But here the initial problems being
addressed tend to be excess effort (against the hammer return spring) to
depress the key, and poor key return.
 
The Heintzman I am working on has good key return. Downweight is somewhat
below 50 grams, and I do not recall what the upweight is, but I seem to
remember it being less than 15 grams. There are, if my recollection is
correct, no lead weights in the keys.
 
My inclination is to pursue the same course of action I have used with the
smaller verticals--achieving a target upweight with springs out of the
picture, then regulating the springs to achieve a final result. I think I
should be aiming for a final downweight somewhere in the order of 50 grams.
 
Any suggestions or guidance on this?"
 
Floyd,
I think your previous procedure(s) will work just fine. However, What
condition are the hammers? If they are very worn, then I'd address a new
set of hammers first, since worn hammers are the key to "light actions",
imo.. Personally I think a 50-55 gram touch should put you in the ball
park, IF the action frictions/resistances have been address first.<G>
Lastly, the Teacher is comparing Apples to Oranges, but her heart is in the
right place. The reality is, she should have a Grand!<G> But, I know that
is probably not the real world in this case. Heintzmann Pianos were well
made pianos, with a good deal of thought into their design, so, at least,
you have something to start with.
Regards,


Joe Garrett, R.P.T.
Captain of the Tool Police
Squares R I