© A. Lange & Söhne
These screws previously performed the following functions
- A possibly existent unbalance of the balance can be compensated by the screws.
- The oscillation frequency of the balance can be changed.
Both measures are intended to improve the accuracy of the watch.
Screw balances can be found only in high-grade watch movements. This applies to the past and the present. From today's perspective a screw balance brings no more advantages due to extremely low production tolerances with usual balances. However, some watch movements are still manufactured with screw balances, as they are a feature of high-quality watch movements, and also nice to look at.