Sr. Tamaran earlier sent the same query to the MBSI website.  Here is
what we replied:

Dear Sr. Tamaran,

Making music boxes from scratch will require considerable skill as
a machinist, in addition to the musical skill you obviously possess.
Unfortunately the fair number of books by Arthur W.J.G Ord-Hume, Graham
Webb, Alfred Chapuis, and others do not give much detail on
manufacturing details of disc or cylinder boxes.

None of the books written up to now really tell more than what the
various processes are: pinning, comb cutting, governor construction,
etc.; they do not explain HOW to do these things.   A good place to
start, if you want to see what they do tell you, is with Graham  Webb's
"Cylinder Musical Box Handbook."

A better idea might be to buy from Nancy Fratti (Panchronia
Antiquities) a little hand-cranked 20-notes musical movement which
plays from a paper strip into which you can punch tunes of your own
creation.  This might be fun to experiment with and would give you an
idea of the mechanics and techniques of music box operation and
arranging.  It sells for $55 (plus $4.50 postage).  You can contact
Nancy at musicbox@dreamscape.com.geentroep [ drop .geentroep to use ]
(phone 315-697-5881)