Preston tuners

Preston tuners or machines (also known as peacock, fan, or watchkey tuners) is a type of machine head tuning system for string instruments, named for English cittern (English guitar) maker John Preston and developed in the 18th century.

[1][2] Preston claimed to be the inventor of this design,[3] though scholars note the originator could be the luthier John Frederick Hintz, who advertised such a mechanism as early as 1766.

[4] The tuning mechanism was also used on the German cittern known as the waldzither, and is associated with the early-20th-century instruments built by C. H. Böhm.

The 18th-century incarnation of the design in England arranged the tuning bolts and hooks parallel with each other.

19th-century Portuguese luthiers developed the current fan arrangement to accommodate the extra 2 strings with the octave doubling of the lower courses and narrower fingerboard width; the English instrument had two single strings instead and a slightly wider fingerboard.