How guitar strings are made

A wound guitar string is steel wire wrapped in a second wire, and its six-sided core gives the wrap something to grip.

stations: 6
things upstream: 42
raw sources: 18
steps from the ground: 6

The short version

A wound guitar string has a hexagonal high-carbon steel core and a wire coiled tightly around it. Machines spin the core while laying the wrap wire in an even spiral. For acoustic strings the wrap is phosphor bronze. In one patented method, heating the finished string relaxes stress in the winding and keeps the tone bright.

Draw the hex core

High-carbon steel wire is drawn through a die so that it has six flat sides. The corners give the wrap wire something to grip.

Goes in
Steel wire
Draw the wrap wire

Wrap wire is drawn thin, in phosphor bronze for acoustic sets.

Goes in
Bronze
Fix on the ball end

Many strings end in a ball end, a short brass cylinder that anchors the string at the end opposite the tuning peg.

Goes in
Brass
Wind the wrap on

A winding machine turns the core while the thinner wire is laid around it in a spiral along the length of the string. Round wire gives the familiar bumpy surface.
Heat to relax the stress

In one patented method, the finished string is held at an elevated temperature for a long time. This relieves stresses from the wrapping and evens out the spacing of the coils, so the string keeps its brilliance longer.
Coil and pack

Strings are inspected, coiled and sealed in an envelope or bag.

End of the lineGuitar string

Worth repeating

Before the Second World War, strings for violins, lutes and guitars were mostly gut, often called catgut, though cats were never used as a source.
Round-wound strings squeak under the fingers because of their bumpy surface, which flat-wound strings greatly reduce.
D'Addario first put phosphor bronze into acoustic guitar strings in 1974.