Hi Carl,  Have you ever contacted Mapes String Co. for piano strings?
I did for the first time last year, and have had wonderful results.
The alignment on the piano was just great!

On the hex core wire, I believe that this is round wire shaped into the
hex before winding a replacement string.  If the hexagonal shape were
to be for the entire length of the wire, I suspect that breakage would
be a problem when winding around the pin, or making the tail.  This is
only my opinion, call Mapes to find out for sure.

I talked with the people at Mapes because I thought that the hex core
was a better string than the regular string.  WRONG!  They do not
recommend using the hex core string to restring a piano.  The tone is
not the same.  They use the hex core just for replacement strings, that
are intended to be fitted to the piano, then removed and replaced when
the replacement string arrives.  I use the Mapes International Gold
Wire for all of my restorations, as it is triple plated.  This prevents
surface rust in this humid area.

They do have a minimum order when ordering direct: $10.00 -- they do
make it easy!  I have sent them a single broken string, which was
promptly made and returned.  I shipped my strings for a Knabe Ampico
on a Monday by Priority Mail, and had the replacement set back the
following Monday, and I did not ask them to rush!

For more information on Mapes strings, call Lawrence or Kirk at
423-543-3195

Al Pebworth - Pebworth's Player Piano Center
Chesapeake, Virginia 23323
http://www.pebworths.com