More Scaling Questions

[Stan Kroeker]

Just in case the following query did not come through the list when I
posted it last week, here is a repeat.  If it did come through and there
were simply no takers, my apologies for wasted bandwidth.  (SK)

>Since David Roberts' book, The Calculating Technician, was published some
>years ago, I have programmed his formulae into a spreadsheet and plugged in
>the appropriate data from each piano I rebuild.  The data from the various
>functions he developed (Loudness Factor, Hammer/String Contact Time,
>Inharmonicity of the 4th Partial, Tension and Percentage of Breaking
>Tension) creates some impressive graphs of each function, but I haven't yet
>learned how to manipulate this data to optimize the scale on a given piano.
>
>I understand that others use Dr. Sanderson's formulae for scale analysis
>and some feel that they are more accurate, at least as far as calculation
>of tension and breaking percentage go.
>
>Although I have been told that the scaling software that is currently
>available is suitable (at least for those of you with Windows based PCs), I
>would like to take the discussion of Do-It-Yourself scale analysis to the
>next level.
>
>Would those of you who have modelled their own spreadsheets with either
>Roberts' or Sanderson's formulae care to comment on your procedures?  Which
>functions take precedence?  Smooth tension curve?  Smooth inharmonicity
>curve?  How do you actually manipulate the data?  Do you identify problem
>areas on the graphs and just empirically change wire diameters to see if
>there is any improvement?
>
>There is a fascinating article in the June 1988 Journal on 'Rescaling the
>1905 Steinway Upright' which involves replacing the lowest 2 tenor trichord
>plain wire unisons with copper-wound bichord unisons.  The article mentions
>the Sanderson formulae and gives the reasons for recaling but doesn't
>actually get into the procedure.
>
>Suggestions?  Experiences?
>
>Best regards,
>
>Stan Kroeker
>Registered Piano Technician
>
>Kroeker & Sons Piano Experts
>59 Quiring
>Winnipeg, Manitoba
>Canada  R2G 1Y5
>
>Ph. 204-669-5881