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1

Lesson 7. EtaChron adjustment & regulation

Unitas 6497 clone

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2

3 mm tool steel

Making an EtaChron adjusting tool

0.85 mm

Fret saw cut & file

Helpful to file a ‘flat’ on these two sides

This tool is to turn the regulator pins to adjust how the hairspring bounces between them

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3

Making an EtaChron adjusting tool

3 mm wide tool steel

Helpful to file a ‘flat’ on these two sides so you can gauge how far the tool has been turned

0.85 mm

Harden & temper this tool

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4

Making an EtaChron stud removal tool

2 mm

3 mm wide tool steel

0.7 mm

0.3 mm

This tool is to remove the EtaChron stud

The tool has been hardened & tempered

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5

Making an EtaChron tool

It doesn’t have to be pretty to work!

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  • On most modern watches the stud support is movable and acts as a beat adjuster.
  • Before this beat adjuster is moved there must be sufficient room for the hairspring to moved between the regulator pins, otherwise the hairspring could be damaged.

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Counter-clockwise rotation to adjust/close gap

No clockwise rotation!

Stud glued to the balance spring, not pinned

Turning the stud the correct way depends on the direction of the balance

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Difference in clockwise or anti-clockwise balances

Turn the stud to turn hairspring towards the centre of the balance

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A

B

Rotate ‘B’ to fine tune the position of the outer end of the hairspring which passes through the regulator slot, so the hairspring makes the longest diameter

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A

B

Rotate ‘A’ to fine tune the position of the outer end of the hairspring, so that the hairspring passes through the centre of the regulator slot

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A

B

Rotate ‘B’ to fine tune the effective length of the hairspring which passes through the regulator slot to define adequate clearance

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Adjustments

Video

Not enough clearance in stud ‘B’

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13

Moved stud ‘A’ clockwise to centre the spring in stud ‘B’

Video

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14

Fully opened ‘curb pins’

Video

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15

Properly ‘adjusted’ now curb pins are closed to correct distance

Video

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16

Removal of stud & hairspring

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Removal of stud

First, open up the gap between the regulator pins

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Removal of stud

Then move the regulator as far from the stud support as it can go

Stud support

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19

Removal of stud

Place the balance in the empty movement for stability and firmly grip in a movement holder

Twist the tool deliberately to remove the stud

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Removal of stud

Video

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Removal of hairspring & balance

Use a fine oiler to slightly part the pins

Don’t forget to squeeze the pins back when re-fitting!

Video

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Re-fitting of the stud

Place the stud in the stud support

Then push the stud firmly with a piece of brass back into the notch

Replace hairspring between pins & squeeze back to position

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Re-fitting of the stud

Video

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Regulation and adjustment

DU

CR

CL

CD

DD

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The last little tweak…

DU

DD

CD

CL

CR

This may look close to ideal, but watches run slightly slower on the wrist & may vary in timing some days later when run in all positions

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The last little tweak…

DU

DD

CD

CL

CR

So, when the watch is run on an all positional watch winder you may find some more regulation is needed, because the watch is no longer static. This is only found out over several days!