[pianotech] Jack and Damper Spring Tension Targets

[Gregor _]

That´s what I was wondering about, too. And how do you do it? Do you dismount the whippen including the jack for measuring?

Concerning the damper spring: 40 grams on which damper? Bass or treble?

Gregor

> From: ilvey at sbcglobal.net
> To: pianotech at ptg.org; fg at floydgadd.com
> Date: Tue, 28 Jul 2009 23:24:51 -0700
> Subject: Re: [pianotech] Jack and Damper Spring Tension Targets
> 
> You are actually reading the jack spring tension and then repinning for correct tension?   
> 
> David Ilvedson, RPT
> Pacifica, CA  94044
> 
> ----- Original message ----------------------------------------
> From: "Floyd Gadd" <fg at floydgadd.com>
> To: pianotech at ptg.org
> Received: 7/28/2009 8:47:04 PM
> Subject: [pianotech] Jack and Damper Spring Tension Targets
> 
> 
> >List,
> 
> >I'm still exploring the regulation of my 1966 Heintzman console.  The jack
> >return is REALLY snappy.  I'm trying to identify an appropriate target for
> >the jack spring tension.
> 
> >In a posting dated Oct 15, 2007, Ted Sambell reports that Shimmel recommends
> >a jack spring tension of not more than 30 grams in a vertical piano,
> >measured at the jack heel with the jack being moved forward by the pressure.
> >Optimum damper pressure is indicated at 40 grams, measured at the felt, at
> >the position of normal damper lift.
> 
> >In a posting dated January 2007, Don Maninno distinguishes between the
> >European design (Schwander?) where the jack springs must be strong, and the
> >hammer springs relatively weak, and the American (Pratt Read?) where the
> >hammer spring is relatively strong, the jack springs relatively weak, and
> >the damper spring does not affect the touch very much.
> 
> >So the numerical targets quoted by Ted are presumably for the European
> >design.  Does anyone have numberical targets for the American design?
> 
> >Thanks for any help you can give me.
> 
> >Floyd Gadd
> >Manitoba Chapter

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