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Αρχείο θεμάτων => Ιστορια-Μηχανισμοι => Μήνυμα ξεκίνησε από: stelakos στις Φεβρουάριος 24, 2015, 12:28:00 μμ
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Μy thanks in advance for any thoughts or insight you might provide.
I am hoping that you will help clarify an issue I've been trying to resolve for quite some time now. I have been a big fan of Jaeger LeCoultre for a long time and was considering getting something from their Master line, such as the Hometime or Master Control. At the same time, I am also considering the IWC Portuguese Automatic. After comparing the Portuguese and the Master Hometime, I realized that the Portuguese comes with a Breguet overcoil, while the JLC doesn't. I did some more research and found out that Jaeger LeCoultre doesn't really use Breguet overcoil in its "entry-level" models, while IWC has it in the Portuguese and BIg Pilot, for example.
I have always thought of Jaeger LeCoultre as a more respectable watchmaker than IWC, so their lack of Breguet-type hairspring in most of their watches is quite puzzling to me. The fact that IWC uses Breguet-type hairsprings is really making me consider the Portuguese more. Will you please shed some light on whether it really matters having a Breguet overcoil, and if it should be a major influence in deciding between these particular IWC and JLC watches. I find it very ironic and incredibly frustrating that no salesperson or manager at stores like Tourneau and Shreve & Co even knows what a Breguet overcoil is — one of them even thought it was a Breguet part.
Thank you for your time,
An avid reader and fan of your work.
Well, there are all sorts of ways to be respectable, aren’t there? The Breguet overcoil is one of them but its presence or absence is not prima facie evidence of respectability or the lack thereof.
It was invented (for flat springs anyhow) as you doubtless are aware by Breguet, and put on a proper mathematical footing by Phillips in the mid 19th century; the reason for the overcoil is — simply put — to ensure concentricity of the balance throughout its oscillation, and thus to improve the isochronism of the balance. It succeeds in this, however, at the cost of producing additional height in the movement, which is why it tends to be found in watches that do not pursue thinness as a primary goal.
All other things being equal, the overcoil with mathematically correct inner and outer terminal curves will certainly give better performance, but one can get excellent performance from a flat spring as well, and unless one is really fastidious about a movement adopting as many of the traditional trappings of chronometry as possible (you know who you are), it is no more a necessity than, say, a supercharger in an automobile — nice to have, and absolutely an aid to performance under certain circumstances, but hardly indispensable.
There are certainly diehard chronometry buffs in the world for whom nothing other than a traditionally made and adjusted overcoil spring, fitted to a free-sprung adjustable mass Guillaume balance, driven by a chronometer escapement, will do; such persons generally either collect vintage timepieces, or bespeak a pocket watch from the likes of Roger Smith, or (which is most likely) alternate between bemoaning the dearth of intellectual rigor and craft in modern watchmaking on the one hand, and the shallowness of their purse on the other.