Fw: rescaling reply

[pianoman]

----------
> From: Tom Cole <tcole@cruzio.com>
> To: pianotech@ptg.org
> Subject: Re: Fw: rescaling
> Date: Saturday, September 27, 1997 7:31 PM
> 
> pianoman wrote:
> > Thank you Tom for your enlightenment.  I take it you have a rescaling
program.  Are you selling it?  This is my first attempt tp learn more about
this subject.

Thank you,
James Grebe
> > ----------
> > > From: pianoman <pianoman@inlink.com>
> > > To: piano tech <pianotech@byu.edu>
> > > Subject: rescaling
> > > Date: Saturday, September 27, 1997 5:09 PM
> > >
> > > A few questions for you experienced ones.
> > > 1.  What happens if in the rescaling the number of notes of a given
size
> > > wire changes from an odd to even or vice-versa.  Where does the added
> > hitch
> > > pin come from?
> 
> The idea is to not make wire size changes that require a lot of hitch
> pin changing. I personally don't like to make a change that causes the
> tail lengths to be at a different angle than the original since this
> affects the side bearing on the back bridge pins and also looks less
> than professional. Try not to be too finicky about the ideal wire sizes
> determined by the computer. One less or one more of a particular size
> will never be noticed.
> 
> > > 2.  I understand the rule used to be not to change sizes at a plate
> > strut.
> > > Is this not necessarily true?
> 
> If the dog leg in the bridge is sufficient, IOW, speaking length changes
> go smoothly across a strut, there is no reason to change wire size at
> that time also.
> 
> > > 3.  What happens when the plate is too low and the bridge surface is
> > cut
> > > out for the bridge to fit?  How does or does it at all affect the
sound
> > as
> > > to the size of wire used.  I was under the impression that this was
> > always
> > > a bad thing.  Yes-No?
> > > 4.  What measurements on the scale are taken for measurement.  Point
of
> > > contact in the front and the front bridge pin.  What other
measurements
> > are
> > > needed?
> 
> Wrapped length of wound strings, diameter of wrapped length, diameter of
> core. Also, of course, the diameter of the plain wires.
> 
> 
> > > 5.  Is the re-scaling programs glorified spreadsheet programs and do
all
> > > the different programs use the same measurements and give you a
choice on
> > > in-harmonicity and tension?
> 
> They may use a spreadsheet. They could also be a data base type program.
> The ones I've seen are linked to a charting program. They are all based
> on the same measurements, offer similar choices but may use slightly
> differing string formulas.
> 
> > > 6.  What data do they give you to send away for bass strings?
> 
> The program I devised deals with the English system but some string
> makers require metric. Check with the person you will be dealing with
> what lengths you'll need to specify and whether inches or centimeters.
> 
> > > 7.  Can you take measurements on a strung piano to see just how good
that
> > > scale is for that piano and calculate things like amount of
> > in-harmonicity
> > > and tension level?
> 
> I have done this but it is clearly the hard way: speaking lengths of
> tenor wires are difficult to measure under the bass strings. You can
> measure diameters with digital calipers but if you have a micrometer,
> you may have to let down the tension of some of the strings to measure
> them.
> 
> Some words of caution: don't go crazy changing wire sizes. Adding in
> half sizes is always a plus. Strings that are too close to break point
> (more than about 65%, say) need to be changed. This is easier to do in
> the bass. In the treble, the speaking length really needs to be
> shortened (yeah, right, just move the bridge a little).
> 
> Good luck,
> 
> Tom
> 
> > > Thanks,
> > > James Grebe
> > > R.P.T. from St. Louis
> > > pianoman@inlink.com
> > > "Do it because it is right"
> > .-
> 
> -- 
> Thomas A. Cole RPT
> Santa Cruz, CA
>