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.
List of Matsumoku tuning keys
Matsumoku open gear individual tuner in situ on a 1971 Epiphone 1802T. The tuner is held to the headstock with two 10mm round cross head screws. Note the curved top and bottom edges of the tuner.
Front of headstock view, showing ferrule and elliptical metal button.
1971 Epiphone 1802T headstock with one tuning key removed. Front view. The post hole has an 8mm diameter.
1971 Epiphone 1802T headstock with one tuning key removed. Reverse view. Note the positions of the screw holes in relation to the posthole.
The tuning key with mounting screws.
The tuning key with mounting screws, underside view.
The tuning key, side view with ferrule.
Matsumoku open gear individual tuner, unmounted, with cog and post removed. Top view.
Tuner, unmounted, with cog and post removed. Note the word JAPAN on the underside.
Matsumoku open gear individual tuner disassembled showing all components.
The ferrule / eyelet has an 11.0mm major diameter, 8.35-8.40 minor diameter (grooved section), 6.2mm internal diameter (hole), and is 6.7mm tall.
ferrule underside view.
$55
$55
$45