1. Why Materials Matter in the Escapement
The escapement releases the going train in small, regular steps and transfers energy to the balance. Its wheel and pallets rub and impact continuously, so friction, wear and mass all affect performance. Silicon is attractive because it addresses several of these problems at once.
2. The Properties of Silicon
Silicon is much less dense than the steels traditionally used for escapement wheels, so components can be lighter for the same strength, which reduces inertia. It is not magnetic, so it is not disturbed by magnetic fields in the way that some steels can be. Its surface can be formed with very fine geometry, and it wears in ways that often need less lubrication than metal parts.
Silicon properties in watch components (qualitative)
| Property | Benefit in a watch | Trade-off |
|---|---|---|
| Lower density | Less inertia and lighter parts | Different shock behaviour to be designed for |
| Non-magnetic | Less affected by magnetic fields | Requires careful handling and design |
| Reduced lubrication need | Less friction change over time | Surface finish must be controlled precisely |
| Temperature behaviour | Hairsprings can be more stable with temperature | Depends on the complete movement design |
3. Silicon Hairsprings
Silicon hairsprings are valued for their stability as temperature changes and for their resistance to magnetic disturbance. Their behaviour depends on the geometry of the spring as well as the material, so they are designed and tested as a complete system with the balance and escapement.
4. Trade-offs and Limits
Silicon is brittle compared with steel, so shock resistance must be designed in carefully. Manufacturing requires specialised processes, and repair is more demanding than for traditional metal parts. Silicon is a significant development, but it is not a universal solution, and its benefits depend on the rest of the movement.
5. What to Ask About a Movement
When evaluating a movement, ask which parts are silicon, how the design addresses shock, and how the watch performs across positions and temperatures. Specifications should be read alongside the service and repair arrangements.
6. Tangential Impulse and the Co-Axial Escapement
In a co-axial escapement, the impulse that keeps the balance swinging is delivered by tangential contact between the escape wheel and the impulse jewel or pallet. Because the design separates the escape wheel from the lever, friction is reduced, and silicon components can reduce friction further. The result is a more consistent transfer of energy to the balance, which supports steady timing as the mainspring winds down.