NEW Gotoh SGV510Z-RL5 L3+R3 Tuners 21:1 Gear Ratio Wood Buttons 3x3, BLACK SATIN Single-coil Configurations:

Single-coil Configurations:

Gotoh SG301 MG MAGNUM LOCK Machine Head Set L3+R3 w/ screws 3x3 - CHROME

it is not necessary

Popular since the '60s the  Rotomatic® full-size tuning machines feature plastic keystone tulip buttons

NEW Gotoh SGV510Z-RL5 L3+R3 Tuners 21:1 Gear Ratio Wood Buttons 3x3, BLACK SATIN Single-coil Configurations:21: 1 tuning ratio Set w 6 tuners for 3x3 configuration Large RioGrande Parisandre Wood Buttons ROCK SOLID posts prevent the rocking of string post LUBRI PLATE With a Solid Lubrication Coat, oil has been eliminated keeping the lubrication where it is needed for the life of the tuning machine heads. Includes bushings and screws Made in Japan