Jaeger-LeCoultre Calibre 174 à Gyrotourbillon 2 Mechanical Calibre
* Mechanical manually-wound Jaeger-LeCoultre Calibre 174, crafted, assembled and decorated by hand
* Thickness 11.25 mm
* Parts: 371
* Jewels: 58
* Power reserve: 50-hour
A key feature of the Gyrotourbilon 2: the cylindrical balance-spring with end curves
The second version of the Gyrotourbillon is distinguished by an essential organ: the presence of a cylinder-shaped balance-spring with end curves. This component was invented by English watchmaker John Arnold, who had it patented in 1782. Due to the complexity involved in its production and the difficulties implied by attempts to miniaturise it, this ingenious discovery which guarantees a regular and perfectly isochronous development of the balance-spring was reserved exclusively for marine chronometers and a few generously sized pocket-watches. Innovative watchmakers chafed at this regrettable situation, since its rating characteristics are unanimously considered to be infinitely better than those of a flat balance-spring.
The engineers and watchmakers of the Manufacture proved able to grasp the opportunity represented by the spherical tourbillon and to present a cylindrical balance-spring nestling at the heart of a wristwatch. Combined with the specific advantages of the spherical tourbillon, this innovation represents a breakthrough in the field of accuracy and paves the way for a level of rating precision that is simply unprecedented on a timepiece designed to follow its wearer’s arm movements.
* Outer carriage: aluminium, 60 seconds for a complete rotation
* Inner carriage: titanium and aluminium, 18.75 seconds for a complete rotation
* Balance: inertia of 12.5 mg x cm2
* Balance frequency: 28,800 vibrations per hour