These guitar machines are a triumph in engineering and style. The housing provides a maximum bearing for worm gear and string post. Gear ratio is 14:1. Worm and gear are precision-cut for perfect meshing. This eliminates backlash and slippage. Countersunk tension screw permits players to regulate turning tension to any degree. Gear box has a special lubricant for lifetime, trouble-free service. Includes 5/8' washers, bushings and wood screws.

The introduction of the new Grover locking Rotomatics™ gives you the ease of use provided by a standard tuner and the positive locking of our internal cam post. Simply insert the string through the string hole, pull to tension by hand and begin tuning. As you start to tune, only the locking cam in the string post turns. Once the string is locked, the string post begins to turn allowing you to bring the string to pitch. In less than one revolution of the string post, you will be in tune, to stay in tune.

Grover’s 409 Series of A-style tuning machines offer an impressive combination of vintage charm and modern reliability. This set of 4+4 tuners is for use on A-style mandolins, with a tight 18:1 ratio to deliver a smooth, predictable rate of tuning adjustment. Moreover, a specially designed adjustable worm gear ensures correct tuner alignment — Mandolin players find this feature results in a much-enhanced level of tuning stability. The 409 Series A-style tuners are packed to the brim with old-school vibe, including an open-gear design, rounded washer head buttons, and elegant engraving to pair with your F-style mandolin’s refined aesthetics perfectly.

Grover’s 409 Series of F-style tuning machines offer an impressive combination of vintage charm and modern reliability. This set of 4+4 tuners is for use on F-style mandolins, with a tight 18:1 ratio to deliver a smooth, predictable rate of tuning adjustment. Moreover, a specially designed adjustable worm gear ensures correct tuner alignment — Mandolin players find this feature results in a much-enhanced level of tuning stability. Lastly, 409 Series F-style tuners are packed to the brim with old-school vibe, including an open-gear design, rounded washer head buttons, and elegant engraving to pair with your F-style mandolin’s refined aesthetics perfectly.

Grover Banjo Bridges.