[pianotech] Action ration measuring

[Jason Kanter]

I've been scanning this thread and I have a question about setting the dip
so precisely. What about the relative sponginess of the punching? A hard
blow has a greater dip than a soft blow. I haven't measured, but I would
think you could easily compress a soft punching by 1 or even 2 mm. So you
can get a more precise dip by using a firmer (Wurzen) punching. Is this not
an important factor? Or am I missing something?

Jason Kanter
-- 
*| || ||| || ||| || ||| || ||| || ||| || ||| || |||*
jason's cell 425 830 1561

On Sat, Sep 22, 2012 at 5:47 PM, Dale Erwin <erwinspiano at aol.com> wrote:

>  Cy
>  Bering a simpleton myself, I agree.
>  If a few of us take a few measurements and compare the data. we'll find
> out if"Does this average out the "arc" effects? For accuracy lets all do
> it this way. Use a metric ruler to set the dip at the front of the key.
> remvoe drop screw and let-off button(or crank it out of the way)Then
> measure the hammer rise as accurately as possible.
>   All actions are subject the accelerating action phenomena
> to changing ratios thru the complete range of motion as the capstans is
> moving further from the wip center pin and the increasing leverage efficiency
> in the wip.
>  FWIW...I've had brainiacs more smarter than me compute things to the
> small decimal points and say 6 mm is enough of a sample. Is it? Dunno for
> sure but seems to work.
>
>
> *Dale Erwin R.P.T.
> Erwin's Piano Restoration Inc.
> ***
>  From: Cy Shuster <cy at shusterpiano.com>
> To: pianotech <pianotech at ptg.org>
> Sent: Sat, Sep 22, 2012 5:24 pm
> Subject: Re: [pianotech] Action ration measuring
>
>  Simpler is better -- I like it!
>
>  Is this significantly different from using your existing tool, Dale,
> where you just measure the first part of key travel and hammer rise?
>
>  Does this average out the "arc" effects?
>
>  --Cy--
>
>  Cy Shuster, RPT
> Albuquerque, NM
>
>  www.shusterpiano.com
> www.facebook.com/shusterpiano
>
>  On Sep 22, 2012, at 5:57 PM, Dale Erwin <erwinspiano at aol.com> wrote:
>
> From: Jim Ialeggio <jim at grandpianosolutions.com>
>
>
>  Ron said:
>
> <It always annoyed me that the cumulative leverage of the presumed
> moment arms matched so poorly with Dale's 6mm in/out direct measurement.
> Something's wrong, and I'll take direct first.
> Jim wrote
> My take...the position of half stroke should be determined by 1st
> determining the  full arc the hammer would travel, driven by the key at
> its full dip,  with the hammer unimpeded by the letoff button. Full
> hammer  travel in this scenario is of course more than blow(-)letoff,
> but it exceeds blow as well.
>
>   Jim.
>
> I like the way you think
>
>   Take the let-off button off and toss out the drop screw too. Now nothing is in the way to impede hammer rrise. Now set a very accurate 10 mm key dip, (however one does that) , then set a modest weight on the key to depress it fully, then simply measure the total hammers rise. Likely it will be 55 mm to 65mm. Divide by 10 equals a totally accurate direct measurement figure for action ratio.
>
> Dale
>
> *Dale Erwin R.P.T.
>
> Erwin's Piano Restoration Inc.*
>
>
>
>
>
> Jim Ialeggio
>
> --
> Jim Ialeggio	jim at grandpianosolutions.com978 425-9026
> Shirley Center, MA
>
>
>
>
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