Schaller M6 90 Guitar Tuning Machine
The Schaller M6 90 guitar tuning machine represents high-precision instrument hardware engineered with an upgraded 1:18 gear ratio for smooth, accurate, and stable tuning. Originally setting the global benchmark for sealed tuners in 1966, this updated iteration features CNC-machined components with self-locking drive mechanisms that ensure consistent tension and lasting performance.
Crafted with premium high-grade brass string posts precisely fitted into the housing, the M6 90 offers superior wear resistance and long-term tuning stability. Every enclosed tuner is permanently lubricated with proprietary Schaller special grease, rendering the entire internal mechanism completely maintenance-free.
Installation is streamlined through an innovative stepped M6 flanged washer with a 0.39-inch (10 mm) base diameter that reliably centers the string post through the banjonut without requiring stepped headstock drilling. This mounting design eliminates tilting torque and reduces mechanical stress on both the string post and rear mounting screws while matching legacy M6 dimensions for direct replacement.
| Brand | Schaller |
| Series | M6 Series |
| Model | M6 90 |
| Product Type | Guitar Tuning Machine |
| Gear Ratio | 1:18 |
| Product Weight | 0.79 lb |
| Single Tuner Weight with Button (Small / Large) | Metal (1.27 oz / 1.34 oz), Pearloid (1.06 oz / 1.09 oz), Ebony (1.06 oz / 1.09 oz) including hollow screw |
| Button Bore Hole | 0.17 in (4.2 mm) diameter with 0.14 in (3.6 mm) drive surface |
| Post Material | High-Grade Brass |
| Lubrication | Schaller Special Grease (Maintenance-Free) |




















