Matsumoku open gear individual tuners

Some guitars fitted with these tuners

As fitted to a variety of electric guitars produced at the Matsumoku guitar factory, Matsumoto Japan from the mid/late 1960s to the mid 1970s. Typically solid body 1802T style guitars: Aria Diamond (1802T), Epiphone (1802T / ET-270), Eros (9525), Fandel (H-F702T) - and most likely others.

Chrome plated. These tuners were fairly basic in construction, with a simple plate, cog and post, and elliptical metal button. They are attached to the headstock reverse with two 10mm round cross head screws. These were most likely designed in the mid-1960s, at a time when industrial standards were in flux: Whilst most measurements are clearly metric (the post diameter is dead on 6mm), some are still imperial (the post length is dead on 1 1/4"). The bolt that holds the post to the cog has a pre-1967 Japanese M3 thread (pitch of 0.6mm) - these were in the process of being phased out in favour of a new unified M3 with a pitch of 0.5mm.

Similar in construction to Matsumoku closed gear individual tuners fitted to numerous other models, but note the striped pattern on the baseplate - this only appears on these uncovered tuners. Although both sets of tuners share the same footprint, there are internal differences that make mixing parts (particularly the baseplate and key) impossible.