Early Masterbuilt guitars had simple individual open-back tuners. In 1934 the gold plated upper-end guitars (De Luxe, Tudor and Broadway) had gold plated Grover metal (oval or cloverleaf) buttons. The mid-range guitars (Triumph and Spartan) had nickel plated oval metal buttons. The low-end guitars (Blackstone, Zenith, Royal and Olympic) had three-on-a-strip plastic button machines, sometimes Grover, sometimes Kluson.
The only major change in tuners came with the introduction in 1939 of the 16-to-1 ratio enclosed gears with marbeloid buttons on all guitars from Triumph to Emperor (Epiphone catalog 1939). The mid-range guitars had individual open-back tuners with either metal or plastic buttons (sometimes Grover, sometimes with no-name). The Olympic continued with the three-on-a-strip machines with plastic buttons.
Wiedler wrote us December 2015: “The documented examples in my registry suggest that the Blackstone came with enclosed tuners only for about a year (1940-41). By the time that catalog was published, the Blackstone had already gone back to (cheaper) open tuners.”
Felix Wiedler, NY Epi Reg
Jim Fisch & L.B. Fred, The House of Stathopoulo, 1996, page 77
NOTE: Epiphone guaranteed “All models for the life of the instrument” (catalog 1932), but “metal and other parts that recieve wear, excepted” (catalog 1934), since they don’t last such a long period. So, many of the historic guitars are most likely not equipped with their original tuners anymore. Therefore, the pictures above only show types of tuners Epiphone used over the years. They don’t necessarily show whether they originaly belong to the instrument they are on.