touchweight analysis

[David Love]

Richard:

First I replaced the whippens (the old ones were shot anyway) with Renner 
universal with an offset heel set in the forward position.  The original key 
ratio was about .61 throughout so I moved the capstan as far as I could 
without compromising the regulation too much.  I didn't want to go beyond 
.400 dip and wanted to keep the blow distance fairly standard, thus, I could 
only get the key ratio down to .57.

The strike weights were on the low end in bass going to high in the treble.  
Since the key ratio was fairly high I needed to keep the SW's low in order 
to avoid excess front weighting.  The bass section was almost right and just 
needed to be smoothed out.  The transition to higher SW's started around 
note 33, so starting there I took some weight off the hammers going all the 
way to the top.  By note 50 I was removing about a gram and a bit over that 
in the last octave.  The SW of Note #1 was 10.3 and note #88 4.8.  The 
leading pattern ended up a more standard 3-2-1-0 with front weights 
comfortably under the maximums as outlined by David Stanwood's table.  The 
action regulated with dip of .395" and blow of 1.75".

The action played much more fluidly with less effort and the customer (a 
concert level pianist) was pleased with the improvement.  Though I think 
this was the best solution under the circumstances, it was not the most 
ideal action.  High KR and low SW's, though necessary to get any kind of 
normal feel in this action, is not the most ideal solution for me.  The 
alternative (short of remaking the keys) was to put on an assist spring but, 
I admit, as someone with a fair amount of pianistic skill, I am not yet sold 
on how these actions feel.

Not bad for a beginner, eh?


David Love


>From: Richard Brekne <rbrekne@broadpark.no>
>Reply-To: pianotech@ptg.org
>To: pianotech@ptg.org
>Subject: Re: touchweight analysis
>Date: Tue, 22 May 2001 19:05:39 +0200
>
>Hi there David... was just wondering how your project is going. What did 
>you
>end up doing with this ?
>RB
>
>David Love wrote:
>
> > Attached as an excel spreadsheet is some data on a Steinert 6' grand 
>that
> > has some problems.  The hammers and shanks were recently replaced (not 
>by
> > me) and the customer is not happy with the way it plays.  The action 
>feels
> > very heavy.  I would appreciate any input on solving the problem.  The
> > customer likes the tone so I am reluctant to alter the strike weight 
>except
> > perhaps at the upper end of the piano.  The key ratio is high and I am
> > considering moving the capstan.  The piano currently has a 17mm knuckle 
>and
> > moving to 18mm is another possibility.  Any thoughts?
> >
> > David Love
> > _________________________________________________________________
> > Get your FREE download of MSN Explorer at http://explorer.msn.com
> >
> >   --------------------------------------------------------------------
> >                    Name: Steinert.xls
> >    Steinert.xls    Type: Download File (application/msexcel)
> >                Encoding: base64
>
>--
>Richard Brekne
>RPT, N.P.T.F.
>Bergen, Norway
>mailto:rbrekne@broadpark.no
>
>

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