Touch weight

[Richard Brekne]

Hi Wim...

I see you've had a few responses with formal definitions of BW. But
perhaps you are still wondering just what it is in practice. Perhaps
not.. but suprisingly many seem to not be clear on the point.

Balance Weight is more or less exactly that weight that needs to be
added to the key (at the front) in order to literally balance the key
with the weight of the top action.  If you put a key on a pivot, and
simulated the weight of the top action with dead weight, you'd need to
put x amount of weight at the front of the key to get the thing to
balance horizontally.

It's used as an indicator of just how heavy the action is going to feel
when played.. tho in itself it is rather limited in what it can actually
say about the actions touchweight, as some of our other discussions
readily reveal.

I dont use the word touchweight as synomonous to balance weight btw... I
mean we have one nice term for that already... and "<<touch>>weight"
sort of implies quite a bit more then static balance. Besides, we dont
have a single word term for the weight related dynamics of the actions
touch. So I use touchweight to do that.

One thing nice about Balance Weight tho... if its even, and comprised of
even amounts of UW and DW, then that implies a certain degree of eveness
to the touch. Not neccessarilly as much as perhaps one might expect..
but just so. If you go the next logical step with all this.. you do what
Stanwood did and use Balance weight, and its componet parts, to further
even the touchweight of the action.

What, if anything we end up doing beyond Davids perspectives... remains
to be seen.

Cheers
RicB


Wimblees@aol.com wrote:

>  I've just done complete down and up weight measurement on the new D.
> From C1 - F2, the down weight is between 52 and 55 grams. The rest is
> between 47 and 50, with a few 45's and 46's in the 7th octave.
> Upweight is generally between 27 and 30 grams, with some as low as 25
> and a couple as high as 34. The Piano Action Handbook says down should
> be 51-52 in the bass graduating to 47 in the treble, with up weights
> at 20. After Christmas I'm going to lube all centers and check for
> pinning. Hopefully I'll get better upweight measurements. Is this
> about what you guys are going for? BTW, is TW the difference between
> down and up, or am I missing something in the calculation? Wim

--
Richard Brekne
RPT, N.P.T.F.
UiB, Bergen, Norway
mailto:rbrekne@broadpark.no
http://home.broadpark.no/~rbrekne/ricmain.html
http://www.hf.uib.no/grieg/personer/cv_RB.html