Horological Meandering

cazalea
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Finishing is much more subjective; staring with Geneva Seal

The GENEVA SEAL

We give you the 12 criteria, reminding also that it must be created in the Canton of Geneva:

Compliance with the standards outlined by the Office for the Optional Inspection of Genevan Watches must include the quality of all parts and components of the movement including those used in auxiliary mechanisms. If the watch passes, the Geneva Seal is punched on the on the main plate and one of the bridges. The site varies according to the caliber.

1 All steel parts of the movement must display polished angles, sides parallel file strokes, visible face smoothed and polished. All screw heads must either be polished or circular grained. (This type of finishing reduces friction ensuring no metal filings effect the movement)

2 Movements must be fitted on the going train with ruby jewels in polished holes. On the side of the bridge, the ruby jewels must be semi-mirror-polished. In addition their sinks must be polished. (This ensures that the lubricating oil will spread more evenly increasing the longevity of parts and components.)

3 A sliding stud cap with a round head and neck must secure the balance spring. (This particular condition creates a huge challenge for the watchmaker; however, it does improve the centering of the balance spring and thus improving the adjustment.

4 Fitted or split regulators utilizing a fastening system is required. (This condition prevents the shifting of the index assembly in the event of jarring and thus eradicating any impact on the adjustment of the movement)

5 Geartrain wheels must be beveled on their upper and lower sides and feature polished sinks. If the wheels are 0.15 mm or less in thickness , one-sided (bridge side) bevelling is accepted. (Durableness is increased)

6 Pinion shanks and faces must be polished. (Providing a marked reduction of friction within the movement and protect it against stray filings which may effect the longevity of the movement.)

7 The escape wheel must be lightweight. Larger wheels must be no more than 0.16 mm thick and 0.13 mm for wheels less than 18 mm across. The locking faces must be polished.

8 The ratchet wheel and crown wheel must be finished according to the prescribed models. (Only a select handful of watchmakers today are able to meet this condition.)

9 The use of wire springs are prohibited.

10 It is imperative that the lever's angle of travel must be contained by solid banking, excluding pins or studs.

11 Shock absorbers on movements are acceptable.

12 Regulating systems using a balance wheel with variable radius of rotation are acceptable.

Some of these are philosophical and preclude adventurous watchmakers from trying new things.

Read on the next entry ...

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