Scale design question

[Vanderhoofven]

I have noticed recently that the Baldwin 243 studio, the Boston UP-118S 
studio, the George Steck studio, the Steinway 45 studio, a Kawai studio 
(model number unkown) and the Yamaha P-22 (if I remember correctly) all 
have the first plain steel wire on the treble bridge starting at note D#3.

There are several other sizes of pianos that have similarities in scale 
design.  For instance the Steinway D and several other large grands have 
the lowest plain steel wire at note F2.

Is there a reason for having these similarites in the scale design?  Did 
these companies all copy the same design?  Or is it just because for a 
given size of piano there is an ideal maximum string length and diameter 
for the lowest plain steel string?

Thanks!
David A. Vanderhoofven
Registered Piano Technician
Joplin, MO

On my quest for more knowledge