How harmonicas are made

Hohner still tunes each reed against a matching one on a master plate fixed to a tuning table.

stations: 8
things upstream: 57
raw sources: 19
steps from the ground: 7

The short version

Thin brass reeds are the heart of a harmonica. A cutter profiles each brass strip, and a die punches out the reeds. Reeds are riveted over punched slots in a reed plate and tuned against a master plate. Two plates screw to a comb that forms the air chambers, and metal covers close it.

Mill the brass strips

Strips of rolled brass alloy get their reed profiles milled in. Hohner does this by hand at Trossingen for its classic diatonic models. A reed is a flat, elongated spring, and longer or heavier ones sound lower.

Goes in
Brass
Punch out the reeds

Die stamps cut the individual reeds from the milled strip.
Punch slots in the plates

Slots are punched into the reed plates to fit the reeds closely, because any gap leaks air.

Goes in
Brass
Rivet reeds over the slots

One end of each reed is riveted by hand over its slot so it lines up exactly. The other end stays free to swing through the slot.
Tune against a master plate

Each reed's pitch is adjusted to match the same reed on a master plate fixed to the tuning table. Pitch changes with a reed's length, its weight near the free end, or its stiffness near the fixed end.
Form the comb

The comb is the body that forms the air chambers. Many are ABS plastic. Hohner's Marine Band keeps a traditional comb of pearwood.

Goes in
ABS plastic Lumber
Stamp the cover plates

Covers are stamped from metal to shield the reeds and direct the sound. Some covers are open, and some are enclosed.

Goes in
Steel
Screw it all together

Reed plates are screwed or bolted to the comb, one on top and one underneath, and the covers go on. Bolted plates can be swapped one at a time when a reed wears out.

Goes in
Screw

End of the lineHarmonica

Worth repeating

Richter tuning, still used on nearly every standard harmonica, was created in 1826.
Wooden combs expand and shrink over time, which can crack them and leak air.
Reeds on the inner face of a plate answer to blowing, and those on the outer face to sucking.