Breakdown measurements

[Keith Roberts]

Terry, are you using P-scale or what for your rescaling? What reference
material did you start with? I need to look at the formulas, mathematical
relationships and maybe plot a few graphs so I have some good basics.
Getting inside the machine and seeing how things change when you adjust the
variables can make the thing a whole lot more understandable.
Keith Roberts


----- Original Message -----
From: "Farrell" <mfarrel2@tampabay.rr.com>
To: "Pianotech" <pianotech@ptg.org>
Sent: Saturday, March 29, 2003 1:15 AM
Subject: Re: Breakdown measurements


> Wim wrote:
>
> "In 25 years of rebuilding, I have never rescaled a piano."
>
> And I have never NOT rescaled a piano. Why would you NOT want to rescale
any piano you are rebuilding? IMHO, this would be like purposely never
improving the geometry of actions during rebuilding - it should be one of
the first things you look at!
>
> Terry Farrell
>
> ----- Original Message -----
> From: <Wimblees@aol.com>
> To: <pianotech@ptg.org>
> Sent: Friday, March 28, 2003 1:27 PM
> Subject: Re: Breakdown measurements
>
>
> > In a message dated 3/28/03 11:31:44 AM Central Standard Time,
> > kpiano@goldrush.com writes:
> >
> > > Do I need the distance from the upper or front bridge pin to the hitch
pin?
> > > What backscale dimension would the scale designer find necessary? The
plate
> > > bearing points?
> > >    On the plain tri-cords do I need any more than just the speaking
length
> > > and wire size?
> > >
> > > Keith Roberts
> > >
> >
> > Keith
> >
> > The best and easiest thing to do is to send the bass strings to a
company
> > that duplicates them. Be sure they stay in order. Cut them off at the
tuning
> > pin. When you send them the set, be sure to include the name and serial
> > number of the piano.
> >
> > If you don't want to send the strings, you can make a paper pattern.
It's a
> > little more difficult to do on an upright. The pattern should include
> > indentations of where the tuning pins are, the agraffs or upper hitch
pins,
> > the windings, both at the top and the bottom of the strings, the bridge
pins,
> > and the hitch pins. Again, on the pattern, write the name and serial
number
> > of the piano.
> >
> > If you don't want to use either one of those methods, you can give them
the
> > dimensions of the first bass string and the last bass string, including
the
> > thickness of the core, and the measurements you indicated. It's a lot
more
> > work on your part, and you run the risk that you didn't write down the
> > correct measurements. I would do this only as a last resort.
> >
> > As far as the plain wires, all you need is s the scale. Measure each
string,
> > and indicate how many notes to a string size. You don't need any other
> > measurement, like the distance between the hitch pin and the bridge,
etc.
> >
> > As far a rescaling, that's up to you. It might be more trouble than it's
> > worth, especially on an older upright, unless you are convinced the
scaling
> > needs to be different. In 25 years of rebuilding, I have never rescaled
a
> > piano. I made one up once, when I got a piano without any strings.
> >
> > Wim
> >
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