Method for manufacturing horological balance springs

A method for manufacturing a batch of horological balance springs (2a), the average of whose stiffnesses lies within a predetermined range, which method comprises the following steps of:

• a) forming, in a wafer (1), 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 said predetermined range;
• b) forming, in the wafer (1), systems (3) for indicating a reference stiffness for determining the stiffnesses of the horological balance springs (2a), the average whereof lies within said predetermined range;
• c) determining the stiffnesses of said systems (3) formed;
• d) computing a dimensional correction to be applied to the horological balance springs (2b, 2c) formed, on the basis of the determined stiffnesses of said systems (3);
• e) 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), the average of whose stiffnesses lies within said predetermined range.