Upright Hammer Weight/ Newton

[Farrell]

So far I've played with several sample notes. The keys are weighted in the
back. I set the notes up completely, but without dampers yet. I have not
trimmed the hammers at all. They sound real good - I experimented with
smaller hammers in that location, and with adding weight to the hammer. The
proper hammer as is sounds best. Strike weight - measured al-a Stanwood - is
in the middle of the medium SW range on David's sheets. Measured DW - way
heavy (I have new springs on rail). I simply messaged the new butt springs
until I got 50g DW. Felt real nice. Measured UW, and all are within a gram
or two of 29g. So I guess I'll just adjust the butt springs for targeted
touchweight.

Now how on earth do they decide how to weigh off the keys? It will all
simply depend on butt spring strength. Seems like it would be pretty hard to
get them all exactly the same and then weigh off the keys. Seems like it
would be way better to calculate a key FW - al-a Stanwood - and install
weights based on an appropriate calculation, and then take your little grand
rep spring adjuster and start messaging your butt..... oh, springs that is
until you get desired touchweight.

With a grand at least you have consistent downward pull to balance a key to
(excluding friction variations) when doing a traditional key weigh-off. How
in the world does a factory do it on an upright? Do they just bend the butt
springs to some pre-determined angle, stick it all together, and then get
their weight sets out?

Interesting.

Terry Farrell

----- Original Message -----
From: "Newton Hunt" <nhunt@optonline.net>
To: <pianotech@ptg.org>
Sent: Friday, November 16, 2001 10:33 PM
Subject: Re: Upright Hammer Weight/ Newton


> Hi Joe,
>
> If upright keys are weighted at all they are weighted in the back.  Here
> anyway.  Look at some old uprights, Masons and S&Ss.
>
> The dampers are always taken out during weigh off.  The jack spring is
> too hard to control and in any event touch weight is measured from rest
> to just before the beginning of let off, grands and uprights.
>
> So, that leaves the hammer spring and I know for a fact that spring
> tension does have a profound effect on touch weight.  If you doubt this
> move two springs to one butt and check the feel of the key.  Then remove
> a spring and feel the light touch.
>
> So, I still stand by what I wrote.  I have thought about this issue for
> a few years not being satisfied with most upright touch and feel.
>
> Anyway, have a good weekend.
>
> Newton
>
> Joseph Garrett wrote:
> >
> > Newton,
> > A couple of things I think you are in error on: 1. The spring that
effects
> > upright touch, more than any other is the Damper spring. But, even the
lowly
> > jack spring can effect the touch. 2. The greater mass is NOT on the back
of
> > the key, in uprights, unless it happens to be of European design. We
front
> > weight our keys and the Europeans back weight their keys. I personally
think
> > that back weighting makes more sense, in terms of touch.
> > Regards,
> > Joe Garrett, RPT, (Oregon)