Parts of a Music Box – Cylinder, Comb, Spring, Governor

All 12 parts on the diagram

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Cylinder and comb 5

Cylinder A turning brass roller. Its pins are set to play the tune.
Comb A steel plate cut into tuned teeth. It makes the sound.
Teeth Each tooth is tuned to one note and rings when plucked.
Pins Each pin plucks one tooth as the cylinder turns.
Dampers It stills a tooth that is still ringing, before the next pluck.

Spring and base 3

Spring barrel The drum with the spring inside. Wound up, it turns the cylinder.
Winding key Turning it winds the spring.
Bedplate The metal base that the other parts are screwed to.

Governor 4

Great wheel The large gear on the cylinder's end. It drives the governor.
Governor Gears and a spinning fan that keep the cylinder turning steadily.
Endless screw The worm at the end of the governor's train of gears.
Air brake Two wings that spin on the endless screw. Air slows them down.

How this list was compiled: Every name checked on 2026-09-30, a name kept only where two independent sources use it for this part. (1) Wikipedia, text only: Music box (pins on a revolving cylinder pluck the tuned teeth of a steel comb; spring-wound), https://en.wikipedia.org/wiki/Music_box . (2) Graham Webb, The Musical Box Handbook (1984), searched in full text at https://archive.org/details/musicalboxhandbo00webb (bedplate, comb and its teeth, cylinder, pins, spring barrel, great wheel, governor, endless screw, air-brake or butterfly, dampers, winding lever and ratchet). (3) H. A. V. Bulleid, Cylinder Musical Box Design and Repair (1987), searched in full text at https://archive.org/details/cylindermusicalb00bull (bedplate, comb, teeth, cylinder, pins, spring barrel, great wheel, governor, the endless and its air brake, dampers). (4) Gilbert Bahl, Music Boxes: the collector's guide (1993), searched in full text at https://archive.org/details/musicboxescollec00bahl (bedplate, spring barrel, the great wheel on the cylinder arbor, governor, endless screw, butterfly or air brake, dampers, winding key). (5) Arthur W. J. G. Ord-Hume, Musical Box: a history and collector's guide (1980), searched in full text at https://archive.org/details/musicalboxhistor00ordh (bedplate, comb, cylinder, pins, spring barrel, great wheel, governor, endless screw and air-brake, dampers, winding key). (6) John E. T. Clark, Musical Boxes, searched in full text at https://archive.org/details/musicalboxes002259mbp (comb, teeth, the brass cylinder and its pins, dampers, endless screw, winding key). Licence: own work

The drawing: Drawn for this site on 2026-09-30 from plain geometry; no maker's movement, nothing traced. Licence: own work

How it works

A music box plays a tune by itself. A spring turns a cylinder, pins on the cylinder pluck the teeth of a steel comb, and a governor keeps the speed even.

Read the full guide

Two views, above and side

Numbers 1 to 8 are the works seen from above: cylinder, comb, teeth, spring barrel, winding key, bedplate, great wheel and governor. Numbers 9 to 12 are side views: the pins, a damper under one tooth, and the endless screw and air brake of the governor.

How the tune is played

Winding the key tightens the spring in the spring barrel. As the spring unwinds it turns the cylinder. Each pin lifts the tip of a tooth and lets it go, and the tooth rings its note. The air brake spins against the air, so the spring cannot run away.

The tune is in the pins. Where a pin stands decides which tooth is plucked, and when.

Questions and answers

What is the comb in a music box?

A steel plate cut into a row of teeth. Each tooth is tuned to one note, and it rings when a pin on the cylinder plucks its tip.

What makes a music box turn?

A wound spring in the spring barrel. Turning the key winds it, and as it unwinds it drives the cylinder through a set of gears.

What does the governor in a music box do?

It keeps the speed steady. A train of gears turns an endless screw, and the wings of the air brake on it push against the air, which holds the spring back.

What are the dampers for?

A damper is a fine wire or a piece of feather quill under a tooth. It stops a tooth that is still ringing just before a pin plucks it again, so the note starts cleanly.