Cylinder-Type Musical Box

The inside of the musical box is called the movement.

The picture on the right depicts the basic structure of the cylinder-type movement and it consists of:

Normally made of steel and where sound is being produced.
Strips of protruding metal on the comb is called the teeth.

The revolving part of the movement where the tunes are imprinted on using metal pins.
It is normally made of brass.

Spring Housing
It hosts the mainspring that provides the mechanical power to move the cylinder.

The handle is used to wind the mainspring.

Governor / Air-brake
This is the part that regulates the speed of the revolving cylinder by restricting the speed of the spring release.

This is where all the parts of the movement are being secured to.

Disc-Type Musical Boxes

The picture on the left shows a simplified structure of a disc-type musical box.

The difference lies in the inclusion of the starwheel for the disc-type.

When the disc turns, the protruding pins on the disc would turn the starwheel, which in turn, will strike the teeth of the comb to produce the music.

Earlier version of the disc was made out of zinc. But it was changed to steel later on to increase the strength and durability. It is slightly warped to strengthen the pins.