Adjust the position of the
hairspring so that it passes
through the center of the
regulator slot.
Move the stud support to
correctly position the roller jewel.
Rotate the regulator pin to adjust the
clearance to control the swing angle
of the hairspring.
Adjust the location of the regulator
arm to fine-tune the length of the
hairspring.
Stud
Stud support
Regulator arm
Regulator pin
To adjust the length of the
hairspring, rotate the regulator
pin only counterclockwise (as
indicated with the arrow). While
doing so, make sure that the
hairspring does not lean to one
side.
TECHNICAL GUIDE
Cal. 6R20A
21/24
1. Names of the parts
A: Stud
B: Regulator pin
C: Regulator arm
D: Stud support
2. Rotate B to fine-tune the position
of the outer end of the hairspring
which passes through the regulator
slot so that the hairspring makes the
longest diameter.
3. Rotate A to fine-tune the position of
the outer end of the hairspring so
that the hairspring passes through
the center of the regulator slot.
4. Rotate B to fine-tune the effective
length of the hairspring which
passes through the regulator slot to
define adequate clearance.
A
B
C
D
Maximum clearance Minimum clearance
2
3
4
View from right beneath
the regulator arm
Side view
View from right above
the regulator arm
20
how to Adjust the hAiRspRing