Glossary/Balance Wheel
Balance Wheel
The balance wheel, or balance, is a perfectly poised mass, which oscillates about a centrally fixed axis. In conjunction with the hairspring, it regulates the unwinding of the going train of a timepiece.
The balance is typically of circular form and may be made of a variety of different metals, the most common of which is glucyder. The balance wheel is fixed to the balance staff, with which it shares its axis of oscillation. It is the regular to-and-fro motion of the balance wheel about this axis, maintained by the hairspring and propelled by power from the mainspring through the going train, that allows for time to be divided into strictly equal parts.