Machine head

A machine head (also referred to as a tuning machine, tuner, or gear head) is a geared apparatus for tuning stringed musical instruments by adjusting string tension. Machine heads are used on mandolins, guitars, double basses and others, and are usually located on the instrument's headstock. Other names for guitar tuners include pegs, gears, machines, cranks, knobs, tensioners and tighteners.

This article is about the musical instrument tuning device. For the band, see Machine Head (band). For other uses, see Machine head (disambiguation).

Non-geared tuning devices as used on violins, violas, cellos, lutes, older Flamenco guitars and ukuleles are known as friction pegs, which hold the string to tension by way of friction caused by their tapered shape and by the string pull created by the tight string.

on (with nylon strings), the worm gears are generally exposed; the strings are wound on the pins inside grooves in the head;

classical guitars

Gibson Les Paul

on , where string tension is extremely high, larger, heavier-duty machine heads than those used on guitars are used. Bass tuners generally feature larger knobs than guitar tuners as well; often these are distinctively shaped, and known as "elephant ears". Gear ratios of 20:1 are used often. Exposed gears are much more common in premium bass guitars than in six-string non-bass instruments.

bass guitars

Resistance to usage[edit]

Musicians playing certain instruments, most notably the violin family, (excepting the double bass) remain resistant to the use of machine heads, insisting on the continued use of friction pegs. Such factors as appearance, weight, tradition and simplicity are cited as justification, despite issues with friction pegs slipping out of tune, coming loose or jamming. In the early 2000s, tuning pegs were introduced with planetary gearing inside a friction-peg shaped casing that can be fitted to an instrument without physical alterations. While reasonably well-accepted, planetary pegs can make string changes more time-consuming.

maker John Preston is often credited with a linear-pull tuning machine, appearing in the latter 1700s

Cittern

(1778–1853) was an Austrian luthier generally credited with creating the worm-and-gear tuning machine

Johann Georg Stauffer

the "Stauffer-style" tuner was brought to the United States by , founder of Martin Guitars (1833)

Christian Frederick Martin

established a Chicago machine shop in 1925, specifically for making tuning machines, with the "Kluson-style" design having each mechanism enclosed in a stamped-sheetmetal shell

John Kluson

(1865–1927) held at least 50 patents for musical instrument parts and accessories. The company he founded (now Grover Musical Products) continued to refine the machine-head concept through the 20th century, particularly a design with the mechanism sealed in a cast-metal shell.