A method for manufacturing an oscillator for a timepiece made from a balance and a balance spring, the method including measuring the average moment of inertia of a batch of balances; providing pinned up balance springs, the balance springs having an excess number of coils forming up to three more turns than the final number of coils; making a first predetermined external cut of the balance springs over a length of one to two coils, then measuring the torque of the balance springs and sorting them according to the value of the measured torque; assembling the balance springs, whose measured torque corresponds to the balances, are assembled to form an oscillator with an intermediate frequency and to determine the length to be cut to achieve the desired oscillation frequency; making a second external cut of the balance springs selected to achieve both the desired oscillation frequency and a target value.

The invention relates to a spiral spring (100), suitable for use in an optical measuring method according to any one of the preceding claims, with several turns (110) which extend along respective circular paths forming a spiral course, wherein the spiral spring (100) can be stimulated to an oscillatory movement, in particular for clocking a mechanical movement, with adjacent turns (110) being deflected relative to each other along their respective circular paths by an angular displacement (), It is the object of the present invention to determine the oscillation behavior of spiral springs based on characteristic geometries, and, in particular, to provide a non-invasive, non-contact measuring method which can be used in automated assembly lines in line assembly in movement production. The object is achieved in that the spacing (x) between the adjacent turns (110) varies at least along a measuring section corresponding to the angular displacement ().

The invention relates to a spiral spring (100), suitable for use in an optical measuring method according to any one of the preceding claims, with several turns (110) which extend along respective circular paths forming a spiral course, wherein the spiral spring (100) can be stimulated to an oscillatory movement, in particular for clocking a mechanical movement, with adjacent turns (110) being deflected relative to each other along their respective circular paths by an angular displacement (), It is the object of the present invention to determine the oscillation behavior of spiral springs based on characteristic geometries, and, in particular, to provide a non-invasive, non-contact measuring method which can be used in automated assembly lines in line assembly in movement production. The object is achieved in that the spacing (x) between the adjacent turns (110) varies at least along a measuring section corresponding to the angular displacement ().

There is provided a method for manufacturing a batch of horological balance springs (2a), the average of whose stiffnesses lies within a predetermined range, and the method includes forming in a wafer the horological balance springs (2b, 2c) with dimensions that differ from the dimensions required to obtain the batch of horological balance springs (2a), the average of whose stiffnesses lies within the predetermined range, determining the stiffnesses of the systems, computing a dimensional correction to be applied to the horological balance springs, and modifying the dimensions of the horological balance springs (2b, 2c) formed, on the basis of a dimensional correction computed to obtain the batch of horological balance springs (2a).

There is provided a method for manufacturing a batch of horological balance springs (2a), the average of whose stiffnesses lies within a predetermined range, and the method includes forming in a wafer the horological balance springs (2b, 2c) with dimensions that differ from the dimensions required to obtain the batch of horological balance springs (2a), the average of whose stiffnesses lies within the predetermined range, determining the stiffnesses of the systems, computing a dimensional correction to be applied to the horological balance springs, and modifying the dimensions of the horological balance springs (2b, 2c) formed, on the basis of a dimensional correction computed to obtain the batch of horological balance springs (2a).