Hi All,  I've used Mapes Piano Strings (in Tennessee) to make every
set of bass strings I've ever changed for the past 20+ years.  I think
I've sent maybe six strings back because there was a loose winding.
However, they were all wound on a round core.

Conversely, I've custom-made maybe a hundred bass strings using
universal bass strings purchased from either APSCO or Schaff.  They
all have a hex core.  I was told by my 93-year-old mentor in the 70's
that the hex core was necessary because you can't possibly wrap the
end of the string tightly without the proper machinery.  So the hex
core was invented so the technician could make temporary replacements
in the customers home.

Once the old string was removed and the temporary universal string
installed, the old string could be sent to a string maker for
duplication and ultimate replacement.  I was never given to believe
that the universal replacement should stay in the piano.

There is at least one very good reason why that thinking seems very
logical to me.  When the time comes to have all the bass strings
replaced, even the best custom-made universal replacement is going
to be wrong to some degree.  Either the wrap will use a different
diameter wire, the core diameter will be different or the total weight
of the string will be different.

With all the technology that has gone into piano string making over
the past 150 years, it seems that if a hex core string was superior
in any way to a round core string, companies like Steinway and others
would have embraced them a long time ago.

My opinion,

John A. Tuttle
www.player-care.com