At 9:34 AM +0200 10/16/00, Richard Brekne wrote:
>Funny that this should come up just now... I bumbed into an article
>by Sam Powell RPT from 93 dealing with this exact subject matter. It
>makes a very good case for this second magic line, and for not
>useing large knuckles due to the increase in friction between the
>knuckle and repetition lever the resulting neccessity of lowering
>the whippen causes.
I'll be glad to re-read Sam's article. Thanks for pointing it out.
The only caution I can think of is that while the change in friction
yielded by such optimization actually read may seem small, the
long-term effects over may years of playing of this axis not being
optimized, may be advanced stretching of knuckle leathers and
flattening of knuckle felts.
> This " rep-center/knuckle-contact/hammer-center axis" as you call
>it was indeed unobtainable (unless a few major parameters were
>changed... hammer bore, an even smaller knuckle etc)
The Aeolean shanks reduced the knuckle to the quarter round quadrant
actually involved in the jack's escapement, thus 50% of the height of
a standard knuckle. This is as much help as this axis can every
possibly get, but probably didn't boost sales of Aeolean's Mignon
grands much. But bear in mind that this "gross dereliction" from this
axis has been built into every other manufacturer's actions, from the
best on down. It's been an unavoidable fact of the post-Erard action
long before we ever knew it was something to protest.
>Still cant help but think that the best results of Stanwoodizing an
>action would be from first assuring best possible top action spread
>configuration before dealing with UW/DW and BW measurements... FW,
>KR, and WBW can be taken independently. Guess I am just going to
>have to "experience" this on my own.
The best I can offer is to see what improvement in friction and
weight the optimization of these axes gets you, compared to the
leverage and weight corrections indicated by Stanwood analysis. It's
the latter which does the heavy lifting.
And before I forget it, Terry is probably still wondering what the
trade-off is, as you drive the SBR to 5.5:1 and below. This is where
the dimension of distance re-asserts itself. The lower the SBR, the
more keydip you'll need to properly regulate the action. Your lower
limit is how much below a 1-3/4" hammer blow you can set and still
get the action in under the pinblock, or making the trade-off at the
front end of the lever train, how much taller you'll let the sharps
get above the naturals, a divergence which grows as keydip deepens.
How's that for Karmic Irony!
Bill Ballard RPT
NH Chapter PTG
"Lady, this piano is what it is, I am what I am, and you are what you are"
...........From a recurring nightmare.
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