[pianotech] Upright Key Weighting

[Mark Schecter]

Hi, Floyd.

I've done this several times with good results. I would try the clips
first, because you probably will be happy with the result. Also, though
you could achieve the static downweight with mass at almost any
location, adding the mass to the hammer gives the most natural feel, 
because the hammer is the part the player is trying to control, and the
proportionality of the response at all different rates of acceleration
makes the most intuitive sense to the player.

I put the clip on with the opening toward the string. This helps keep
the clip tight against the shank, because when the hammer strikes the
string and the shank suddenly stops, the momentum of the clip tends to
keep it going, tightening it.

The only problem is whether there is enough shank showing above the rest 
rail for the clip, without the clip holding the shank off the rest felt. 
If not, you will have to adjust lost motion and/or possibly the rest 
rail's resting position. You might want to remove the rail for ease of 
installation.

You could offer your client the idea that the clips are a quick and easy 
way to try to achieve the desired result, that is easily and quickly 
reversible if they don't like it. If they do like it, you could offer 
to, after a trial/proof period, remove the clips and add permanent 
weight to the hammers by the usual methods, but so far, for me, everyone 
has been happy with the clips, and has chosen to not bother with the 
last step.

Small binder clips are too large to grip the shank. The size clip I use 
is the Mini, which is snug on the shank and weighs about 1 gram, adding 
about 5 grams to the downweight, just enough that they will feel it, but 
not so much that one is already too much. You can use two or even three, 
but as they accumulate toward the butt center, the effective weight 
added diminishes. You can get 'em by the 100 at the big box office 
supply stores, I would take at least 200 in case they want more 
immediately.

~Mark Schecter

On 1/19/12 7:16 AM, Floyd Gadd wrote:
> So increasing the mass of the hammer (or adding a clip on the shank)
> or adding mass at the back of the key will both require more force to
> achieve acceleration.  What are the tradeoffs in choosing where to
> add the mass? Adding a clip to the hammer shank is quick.  It will
> change the interaction of the hammer and the string at the point of
> strike, for better or for worse, in terms of tone.  Adding mass to
> the key stick will improve key return, if that is a problem.  In this
> case it is not.  For what it's worth, I recently needled and shaped
> the hammers.  They are original, but not obviously screaming for
> replacement. I am considering my strategy for Monday morning.  I
> think I should start with the clips, and see how my client evaluates
> the result.  I can also find a temporary way to fix weights to some
> keys, and get a response to that if necessary. Off the top, some
> evaluation and adjusting of friction (key bushings and butt flanges)
> on selected notes will give a foundation for what follows. I hear
> both static touch weight (as measured with my weight set) and dynamic
> touch weight (how much force is required for acceleration, as
> evaluated subjectively by the player) as being significant
> considerations. Any further suggestions as to setting priorities?
>