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MMD > Archives > October 1998 > 1998.10.07 > 16Prev  Next


How to Build a Custom Music Box - "Foreverbox"
By A. Thomas Tran, forwarded

Here is that write-up An Thomas Tran promised me about his work building
an 18 note music box with a custom tune.  I'm afraid he overstates my
own participation (I mainly just cheered him on - but I did suggest the
clay idea, he added modestly).  It is a good write up of an idea that
really worked.  The Foreverbox .WAV itself is available at the MMD
website already, as well as at Thomas's own site, whose URL is listed
at the end.  This should serve as the definitive answer to a real FAQ.

Regards,

Larry Smith

 - - - Begin Forwarded Message - - -

 Date: Sun, 04 Oct 1998 19:37:57 -0700
 From: An Thomas Tran <unity303@ucla.edu.geentroep>
 To: Larry Smith <lcs@zk3.dec.com.geentroep>
 Subject: Re: Foreverbox write-up

 ---------------------------------------------------------------------
          FAQ: How To Make a Customized Music Box Tune
 ---------------------------------------------------------------------

One day I decided that I would make a music box.

It seemed a pretty simple task with a crystal clear objective: make a
music box that, upon opening its lid, would play a tune called "Forever"
written by someone I care for.  But there was no word from anywhere
telling me that "Foreverbox" wouldn't be complete until over two years
after I envisioned the project.  I was never told of the opposition I
would face.  I was never told there were no clear directions, no
resources or human beings I could refer to for guidance in building this
music box.  I could probably tell you about the obstacles faced, the
purity of love Foreverbox stood for, or the utter joy and beauty felt in
finishing the project and giving it as a gift, but we'll save that for
those of you who actually might care enough to hear about it.

The point of this shabby introduction is this: I wanted everyone who is
willing to make a music box to be able to have the resource I wish I
could have had.  Going through the project alone wasn't easy, but it
doesn't have to be harder than it needs to be, especially when someone's
willing to help out.  Here it is: "How I Made My Custom Music Box Tune."

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

I want to mention that this FAQ took several months to write.  It was
difficult trying to think of ways to explain the unexplainable
"Foreverbox".  I want to apologize to those of you who expected the
release long ago.  I would like to thank many people, but particularly
May Chen, who shared with me the beauty of "Forever".  Foreverbox would
never have been, without you.

Thank you.

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

THE MOVEMENT

The first step for me was to write a realistic music box arrangement for
the selected tune.  I suppose when I say realistic, I mean that I had to
keep in mind that the music box repeats, and each repeating loop lasted
about 15-17 seconds (for the specific music box I used).  Also, it is
not possible to have two notes quickly played consecutively, unless
there's more than one tooth on the comb emitting the same frequency.  In
fact it's even a bad idea to have the same note hitting anytime within
about one second of the first hit.  The first hit makes the note ring,
the second hit will cut the ringing short.  This is probably very clear
if you take a look at the music box movement.  (I refer to all the metal
stuff attached to the wooden box as "the movement".  It is the essential
part that generates music).  At first, I wasn't bright enough to realize
the problem of playing consecutive notes, and my first results of making
the music box weren't pleasant

Furthermore, I ended up having to rewrite the arrangement in a simple
form of melody and chords, because of restrictions of the limited notes
on the combs, which leads into the following section.

THE COMB

Take a look at the movement.  The comb is the piece of the movement
that has teeth on it, usually some multiple of 18 teeth.  The 18-note
combs usually have one or two fat screws that attach the comb to the
rest of the metal movement.  The trickiest thing about a comb is that
each comb has a different set of notes.  This means you need a very
discriminating ear to make certain that the comb you choose will support
the mandatory notes of your custom tune.

I had a lot of trouble finding a comb that matched the same notes I
needed to complete Foreverbox.  To illustrate, Forever has these
mandatory notes: C, D, E, F, G, and A.  The chords are: C, A, F, and G.
(Of course, you can always transpose and maintain relative pitch.)

At first I bought a movement for "Memories" but after a more
scrutinizing review, I found that the comb lacked the necessary "D"
melody note I needed for Forever.  I had to rearrange the piece so that
the tune would have to match the specifications of the comb, although it
should have been vice versa.  Anyhow, two years after I bought the comb
for Memories, I realized that I could buy metal movements alone,
*separate* from the wooden boxes, for a cheaper price.

Places like San Francisco Music Box and Richter's seem to sell movements
for $10.00 - $15.00.  These guys carry hundreds of movements for dozens
of songs, so after I found out this information, I had no excuse
for an inappropriate comb.  I ended up with the movement for
"Anniversary Waltz" which was what I stuck with until the final
product.  The arrangement was rewritten so that the accompaniment
matched the notes on the comb.

JAPANESE/SWISS MOVEMENTS

Another word about the movements, I found that there are two kinds of
movements that dominate the low-end music box market: Japanese and
Swiss.  The Swiss ones I have seen are also called "Romance" movements,
and the Japanese movements are made by a company called Sankyo.
Richter's wanted more for the Swiss movements, perhaps the quality is
somehow better, but I don't know much about the differences between the
two.  I used a Sankyo movement for Foreverbox.  I believe that although
the mounting points are the same on Romance and Sankyo movements, the
other parts of the movement, like the comb or the cylinder spool, are
not interchangeable between the two types of movements.

THE CYLINDER SPOOL

Onward to the next and most important part of the movement: the cylinder
spool.  Again, if you know what a movement looks like, it's probably
easy to point out the spool.  It's the cylinder with all the tiny
protrusions.  Powered by a windup spring, the spool rotates about its
axis, while the protrusions lift and release specific teeth on the comb
to emit sounds.

REMOVING THE SPOOL

I would like to mention that spools should be relatively easy to remove
from the movement.  Usually, you can somehow "unscrew" some metal piece
that is opposite the side of the windup spring.  I believe that on the
Swiss movements, removing the spool is as simple as removing screws.
However, on the Sankyo movements, it is not obvious.  It doesn't require
any drilling procedures or Krazy Glue restorations (I wish I knew that
the first time around).  Look closely.  There is a small, hollow metal
cylinder that holds the spool in its place.  It's opposite the side of
the windup spring.  After a long time, I realized that the cylinder had
threads on the outside surface like a screw.  Using a small pair of
pliers, you can twist the cylinder little by little, and the spool will
become more and more loose until finally the spool is free.  Replacing
the spool is simple once you figure out how to remove the spool.

MAKING A NEW SPOOL

This is where I spent most of the time physically and mentally working
on the music box.  I spent a good estimated 100+ hours physically
working on this section.  The main goal is to make a whole new spool for
the movement to replace the old.  _This_ was the biggest obstacle to
overcome.

I once asked my physics teacher in high school how I might go about this
and he gave some suggestions, like "super glue can work wonders" but
unfortunately none worked out.  I scoured the phone book, called many
places (metal shops, woodshops, clockmakers, clock repairers) but they
all told me that they didn't handle such physically small
perforations/protrusions like that.  One company told me they could make
the spool from specific engineering blueprints in a flat metal form with
protrusions, but would not be able to bend it perfectly into a cylinder
without ruining its shape.  I went to music box stores that turned me
down, some even said it would be impossible to do it.  Reuge Music said
they would make 100 cylinders for something like $2500 but that was
entirely unrealistic.  I'd given up the project after being discouraged,
but new hope sparked within me every so often.  One such spark led me
to do massive Internet researching and e-mailing, which I hadn't thought
about as a resource until then.  Of the many responses, I was grateful
that there were three resources responding with positive comments.

The first was Margeret Marcus from "The Music Box Shop".  She suggested
that I look around in libraries for books on this.  The closest thing I
found at the UCLA Music Library were books on _restoring_ music boxes.
Reading these books helped me understand more about the movements and
gave me ideas on how to create my own cylinder.  (It also allowed me to
realize how difficult a task I was taking on, and that it would be
downright impossible to find a how-to-guide-build-a-cylinder text.)

Second was Danilo Konvalinka, from "Music Wonderhouse".  Danilo was
extremely helpful in giving me information about how music box spools
were originally made back in the days before spools were factory
produced.  The most important information that Danilo gave me was this:
the protrusions on the cylinders were made by inserting small pieces of
cut music wire into drilled holes on a hollow metal cylinder.  The
cylinder was then filled with cement, so that the cut music wire "pins"
would stay in their place.  To come to a resolution, I combined this
with a technique I was given by:  Larry Smith.

Larry was the most hospitable of those who responded.  I truly thank him
and ask that you recognize his direct significance to the completion of
the project.  Larry seemed to deeply care about this project, and seemed
to love writing detailed explanations on all the suggestions he could
think of.  In fact, it was he who proposed that I write up a
how-to-build-a-music-box kind of thing.   What you're reading is the
product.

THE WONDERS OF POLYMER CLAY

Larry suggested that I make a cylinder completely out of polymer clay.
Polymer clay is a kind of plastic that bakes to hardness in 15-30
minutes in home ovens at 275 degrees.  It can be found at any arts &
crafts store (i.e. Michael's).  A few brands of polymer clay are FIMO,
Sculpey, and PROmat.  I used PROmat.  Two ounces of PROmat (~2 dollars
per two oz.) was enough for me to practice and finish a few cylinders.
I think it's awesome that the clay is so affordable.  Anyhow, Larry
commented that maybe I would be able to bake the protrusions from clay,
but when I made an effort to do this, I discovered that the clay clearly
did not have enough strength to bear the torque of the spring against
the comb.

Improvising from the two given solutions gave me this: instead of baking
a hollow cylinder, bake a solid cylinder spool and stick small wire pins
in it!  Alas, an ultimate solution after two gloomy years of failure.
Still, problems still remained unresolved.  Where would I find the music
wire pins to stick into the cylinder?  How would I be able to bake a
perfect cylinder the exact size of the movement?  How would the clay
cylinder mount onto the movement as a spool?

AT LAST, A TECHNIQUE TO MAKE A SPOOL

Let me tell you now, this part gets extremely tricky.  Although I can
tell you exactly what worked for me, it's not guaranteed it will work
for you.  You may not be able to find the corresponding parts so you'll
need to use your creativity.  I believe you can easily find the music
wire at most hardware stores.  I found my wire at Orchard Supply
Hardware (OSH).  OSH sells these things in packages that are probably
enough for you to make a couple hundred spools.  The thing is, for each
protrusion, you only need about a quarter of an inch of wire, and the
wire I found came only in packages of ~200 ft. for five bucks.

By the way, after I finished Foreverbox, I had a _lot_ of leftover wire.
If you're in need of wire, I am more than happy to share it with you,
just send me an e-mail telling me where I can send a dozen strands of
wire, and I'll be glad to mail them free of charge.  The wires that I
bought can only be used with Sankyo movements, however.  The Romance
movements seem to have larger pins and teeth.  By the way, if you still
don't get what the music wire is for, it'll become clearer later as I
explain more about the spool-making process, so don't worry.

I've found that for the newer Japanese Sankyo combs, you want music wire
that is .020" in diameter.  Wires that are too fat in diameter will have
problems because they may accidentally affect an undesired tooth.  This
small size also seems to help because of the increased accuracy when
poking the wire pins into the clay cylinder.  It seems it's much harder
to be accurate when poking large pieces of wire into the baked clay
cylinder.

At OSH, I also found what I needed to be able to bake the clay into
perfect solid cylinders.  I was *extremely* fortunate to find this.  It
is a piece of dark-gray plastic that looks like a hollow cylinder piece,
except one of the ends has got additional plastic that makes the thing
look sort of like a teeny gray top-hat.  Except it looks like a top hat
with the top cut out, so that you can stick your pinky through one end
and see your fingernail pop out on the other.  It's called a "Reducer
Bush".  I'm not exactly sure what real function of the reducer bush is,
but I know it has to do with small wheels and axles (maybe for
furniture).  Anyway, here are more details about the product:

5/8 OD, 1/2 ID
Reducer Bush
$2.79 Each

Brand: California Caster
Color: dark grey

5/8" O.D. x 1/2" I.D.
part no. 1/2 - 5/8 reducer
adapts 5/8 bore wheels to 1/2 axle
bar code: 7 80194 00027 6
OSH code: 0 37049 91338 1
OSH product # (?): 257-7344

Now the project of making the cylinder is going to be split into two
parts.

    1) Make the left half of the cylinder
    2) Make the right half of the cylinder

It doesn't really matter which is left or right; what does matter is
that you make the two pieces separately.  After you bake each piece, you
need to Krazy Glue the two pieces together.

The question now: how do I shape the two molds of cylinder so that
they'll fit perfectly into the movement?  Referring to a Sankyo
movement, take a look at the cylinder spool you removed.  There are two
plastic chassis that hold on to the metal spool.  Remove the two
pieces.  Very clearly, they are not identical.  You need to use each of
those pieces to hold the baked clay in its place, in a way that allows
the clay to spin about the axis of the original metal piece.

Stuff the top-hats with clay.  Pack it in tightly!  Now press one piece
of the plastic chassis against one of the two holes of the top-hat.
Make sure the plastic chassis is centered _perfectly_.  This is
important, and the reason will be clear later.  Now push the clay into
the plastic chassis, from the other side of the top-hat.  Remove the
plastic chassis and you'll have a negative impression of the plastic
chassis.  The side that does not have the negative impression can be
cut off with a sharp blade or razor.  Now is the time to bake it!
Remember to remove the plastic chassis.  I'm not sure whether it will
melt, but I'm not sure you'd want to risk it either.  You can bake the
clay along with the top-hat, the top-hat doesn't seem to melt.  After
the baking, remove the clay from the top-hat.  By this time, you
probably see what's going on now.  The negative impression will fit
perfectly into the plastic chassis.

Do the same with the other plastic chassis.  After baking it and
removing the clay from the top-hat, try sticking the two baked pieces of
cylinder together (don't use glue yet).  Attach the plastic chassis to
each cylinder.  You'll notice that the clay cylinder you've made is too
long to be able to fit into the movement.  Use a razor to cut off some
clay from one of the cylinders, until the two things will fit.

If you're sure it fits, you can Krazy Glue the two pieces of clay
together.  This is your new clay cylinder.  It should mount perfectly
into the movement, and it should rotate perfectly.  Be sure that the
cylinder doesn't interfere with any of the teeth on the comb.  If the
cylinder does interfere, your best bet is probably to learn from your
experience and try baking another.

WHAT ABOUT THE PINS?

Now that you've chosen your comb, write a musical arrangement of the
song.  Make sure that every note you choose is a note that can be
emitted by one of the comb's teeth.  Be sure that no two teeth are
consecutively hit within a single beat.

You've got an arrangement.  Now the project gets insane (not unlike
before).  Where will you pin on the cylinder?  Cut out a piece of
paper that you'll be able to roll perfectly around the clay cylinder.
Remove the piece of paper, and on the paper, make a tiny graph that
portrays time vs. teeth, like so:

-x----------x-----
----x-------------
--x---------------
----x-------------
-x------------x---
----x-------x-----
--x--------x------
----x-------x-----
etc.

When the paper is rolled around the cylinder, it should indicate exactly
where you need to pin.  The graph needs to be perfect.  There is little
margin for error.  Any mark that is just a bit off will cause the tooth
to be released too early or too late. Also, the pin might end up
interfering with wrong teeth.

Since the graph demands such perfection, I used Microsoft Word to make a
graph, and printed it out.  You can use my Word document as a template.
This is a copy of the original document I used to make "Foreverbox":

    http://www.ben2.ucla.edu/~unity303/musicbox/forevergraph.doc

Use Word to make your graph, print it out, and cut it to size.  Use tape
conservatively to hold the graph in place perfectly around the cylinder.

NOW THE PINNING PROCESS

Wooowhee!  We're almost there!

Cut out a quarter-inch piece of music wire.  File it down for about a
half a minute against a metal file.  Then pin the wire into the clay, in
accordance with the graph you've taped around the cylinder.  You need to
be sure the music wire is filed well so that it does not cut into the
teeth!  If the music wire is still sharp, it will detune the tooth, and
eventually the tooth will break off.  I experienced this misfortune and
had to replace the comb.  Another situation that will cause the teeth to
break is if you don't push the pins in far enough.  A pin that lifts a
tooth too high will cause the tooth to experience a torque so great that
the tooth will eventually snap.  When this happened to me, I had already
completed the first version of Foreverbox.  Before giving Foreverbox as
a gift, I tested it for hours.  On the third day of testing, two teeth
snapped, and one of the notes was detuned a whole half-step down.  I
was quite disheartened.  This is my warning to you.

This section may seem simple, but I want to mention that this alone is
the most time-consuming portion of the project.  Be patient!   You're so
close.  It took me years of devotion to get this far, and if you're
going to let go of it, somehow it doesn't seem fair.

Listen to the movement after you insert each pin!  You need to check
that the tempo is consistent, the correct tooth was hit, and the note is
not lifted too high.  I know this takes forever, but that is the only
way you will know.  It's very easy to incorrectly pin, and end with poor
results.

Here are a few suggestions for this section: if you want to get an idea
of how high the teeth can be lifted before breaking, look at another
Sankyo/Romance movement that hasn't been tampered with.  Look back at
the movement you've made and check that the lifting height is similar.
Also, if you can help it, don't ever unscrew the comb.  I believe that
leaving it in its original position will make it easier to compare
lifting heights, which may prevent breakage.

When I was done with Foreverbox, I removed the paper graph and I coated
each pin with Krazy glue, to make sure the pins would not move around
after years of play.  After Krazy Glue, I tested the music box for
several days to be sure Forever would really be.

Find a music box, one without a movement.  Again, you can buy the boxes
at Richter's and San Francisco Music Box Factory.  I believe most boxes
have screw-in points so that you can mount your own movement into the
box.  Once you screw it in, you'll be done.

Wind up your box, and be ready for the most beautiful thing you've ever
heard.

CONTACT ME

If you get stuck, you're not alone.  I will be glad to help: find me at
unity303(@)iname.com.  I check my mail daily.

Oh yeah, if you ever want to know more about the story behind Foreverbox
that I left out, you are more than welcome to ask about it.  I would be
very happy to respond to an e-mail if you're curious.  I also have ICQ
and AOLIM.  Ask me.

I would also love to hear about your progress on your own music box.
Even if you've merely read this FAQ, let me know.  I don't expect very
many people to read this, I want to see how things turn out.  Thanks!

Be sure to visit

    http://www.ben2.ucla.edu/~unity303/musicbox

where you'll find the latest version of this FAQ-like guide.  The text
is accompanied by extremely helpful images.  You can even download a 29
second 44.1khz 128kbit .MP3 of Foreverbox.

Feel free to make suggestions, corrections, and additions.  I'll follow
up immediately and accordingly.

Thank you for reading.

Copyright 1998.  By A. Thomas Tran.

 [ Thomas,
 [ Thank you for writing!     -- Jody


(Message sent Mon 5 Oct 1998, 16:13:30 GMT, from time zone GMT-0400.)

Key Words in Subject:  Box, Build, Custom, Foreverbox, How, Music

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