Key (instrument) Key (instrument) A key is a specific part of a musical instrument. The purpose and function of the part in question depends on the instrument. On instruments equipped with tuning machines, violins and guitars, for example, a key is part of a tuning machine. It is a worm gear with a key shaped end used to turn a cog, which, in turn, is attached to a post which winds the string. The key is used to make pitch adjustments to a string. With other instruments, zithers and drums, for example, a key is essentially a small wrench used to turn
Musical instrument and handicraft cannot determine which instruments are more "primitive". Ordering instruments by geography is also not totally reliable, as it cannot always be determined when and how cultures contacted one another and shared knowledge. Sachs proposed that a geographical chronology until approximately 1400 is preferable, however, due to its limited subjectivity. Beyond 1400, one can follow the overall development of musical instruments by time period. The science of marking the order of musical instrument development relies on archaeological artifacts, artistic depictions, and literary references. Since data in one research path can be inconclusive, all three paths provide a better historical