> What determines the length of a music box barrel spring?

In response to Alan's question regarding the length of a spring,
there are several factors one must consider.  At the top of the list
are the diameter of the barrel, the thickness of the spring material
and the size of the center arbor.

Over the years my son John and I (Wind Up Music) replaced springs
for many dealers and collectors alike.  I can tell you it is not
a do-it-yourself project.  We sold off the business years ago but
the thought of a 22 foot long, .032" thick, 2" wide spring (typical
Regina disc box) exploding out of a tightly wound core is excitement
that one can live without.

It's been many years since we've been out of the business, but I recall
that the delicate cylinder boxes had springs fairly thin and longer to
allow longer playing times, while the heavy duty jobs of lifting discs
and or turning large machines called for thickness of .032" and beyond.

Back then we had charts giving the length and thickness of springs
for various music boxes.  They are out there.  Also, in the MBSI
Journal several dealers are advertised as spring repair specialists.

Hope this helps.

Bill Zuk (Enjoying the good life in Sunny Sarasota, Florida.)