Teardown, The World’s Thinnest Automatic Chronograph

Today, I want to talk about a very beefy watch, the Bulgari Octo Finissimo Chronograph GMT. The Bulgari Octo Finissimo Chronograph GMT is the world’s thinnest automatic chronograph, breaking the world record. Someone has disassembled this watch abroad, and we can take a look at how the Bulgari Octo Finissimo Chronograph GMT is the thinnest in the world.

The Bulgari Octo Finissimo Chronograph GMT is the thinnest automatic chronograph in the world.
Before I start, I want to highlight a few points about the Bulgari OCTO:
 1. Bulgari belongs to the LVMH group, and is a brother brand with Tag Heuer, Zenith, and Hublot. In addition, Bulgari has successively acquired independent watchmaking brands such as Jero Zunda and DANIEL ROTH. In terms of watchmaking, it has very strong technical strength.
 2. Bulgari’s main men’s watch series OCTO was designed by Master Jero Zunda. Jero Zunda has designed famous watches such as Audemars Piguet Royal Oak, Patek Philippe Nautilus, IWC Engineers, and Omega Constellation. Master’s hand, the octagonal appearance recognition is very high.
 3. Bulgari is one of the three major jewelry brands in the world. Like Cartier, Bulgari is very strong in watches and jewelry.

The Bulgari Octo Finissimo Chronograph GMT chronograph, with a thickness of 6.9 mm, is currently the thinnest automatic chronograph.
Teardown of the Bulgari Octo Finissimo Chronograph GMT.
 Octo Finissimo Chronograph GMT chronograph is the world’s thinnest automatic chronograph launched in 2019 by Bulgari. The watch is 6.9 mm thick and the BVL 318 automatic chronograph movement is 3.3 mm thick. For example, the thickness of the entire Bvlgari watch is about the same as that of the Rolex 3135 (calibre 3135 is 6 mm thick), and the Bulgari Octo Finissimo Chronograph GMT is an automatic chronograph. Hour function, power 55 hours. Titanium case, price 142000.

The Bulgari OCTO series was designed by Jero Zunda.
 The Bulgari Octo Finissimo Chronograph GMT has a Bulgari signature octagonal case with a round bezel. The timing button on the right side of the case is symmetrical to the two-time button on the left side of the case and blends into the shape of the entire watch, which is very clever in design. At 3 o’clock on the dial of the watch, there are two-time hands, 6 o’clock is a 30-minute chronograph, and 9 o’clock is a small second hand.

The Bulgari Octo Finissimo Chronograph GMT chronograph uses a self-torque edge, which has no obstruction to the movement and reduces its thickness.
 Looking at the back of the watch, we can see that the Bulgari Octo Finissimo Chronograph GMT chronograph uses an edge automatic rotor, which is located on the outer ring of the movement. While reducing the thickness of the movement, it has no obstruction to the movement and is very beautiful. From the figure we can see that after separating the case and the bezel, there is a circle of ‘rubber ring’ under the bezel, which is the waterproof rubber ring of the case.

We can see that after removing the bezel, the waterproof rubber ring in the case.
 Take out the movement, we can see the front and back of the movement intuitively. On the dial side of the movement, all the movement splints are decorated with pearl patterns. At the same time, we can also see that on the front of the movement, there is a very long curved lever. This is the lever that controls the function of the two places. When the two-time button (9 o’clock case) is pressed, this lever will push the two-time gear to adjust the time in the second time zone.

Function lever on both the front of the movement and the front of the movement.
 The Bulgari Octo Finissimo Chronograph GMT chronograph uses an edge automatic rotor. We can see that there is a platinum bar weight on the ring of the edge automatic rotor. At the same time, there is a ring of teeth on the inside of the ring. During the rotation, the movement is wound through the teeth and the self-winding gear with the edge of the core. This is the principle of the automaton.

Bulgari edge automata structure.
 The Bulgari Octo Finissimo Chronograph GMT chronograph uses a straddle balance wheel splint. The balance wheel is a ‘light pendulum’. The balance spring is adjusted using the fast and slow hands. The swing frequency is 28800. From the picture, after removing the balance wheel and balance plate, you can gradually see the key part of this watch, the timing mechanism.

The balance part of the Bulgari Octo Finissimo Chronograph GMT.
 We can see that the timing mechanism of the Bulgari Octo Finissimo Chronograph GMT uses a combination of a cylindrical wheel and a horizontal clutch. The combination of a cylindrical wheel and a horizontal clutch is the most traditional technical combination in a chronograph. Many modern chronographs use vertical clutches, but in order to reduce the thickness, Bulgari chooses horizontal clutches and thins parts in traditional technology.

The chronograph mechanism of the Bulgari Octo Finissimo Chronograph GMT uses a cylindrical wheel and a horizontal clutch.
 However, it is worth noting that despite the thinning, Bvlgari has not made any concessions on the key timing mechanism, and uses very large and sturdy parts. We can see that both the horizontal clutch clutch gear lever and the lever connected to the cylindrical wheel to control the start / stop / zero of the chronograph are very stout. It can also be seen that the ultra-thin watches are all “reinforced” on the core functional components.

The core timing components of the Bulgari Octo Finissimo Chronograph GMT are very stout.
 After removing the timing part, it is the main splint of the movement. At the same time, we can also see that the layer of the timing wheel is very thin. The main splint is the most basic timekeeping gear of the watch, including mainspring, second wheel, third wheel, second wheel, escapement wheel and so on. On the main splint, it can be seen that there are pearl patterns on the balance wheel and escapement wheel. The rest is covered by an upper splint, which is decorated with Geneva stripes.

The Bulgari Octo Finissimo Chronograph GMT chronograph removes the timing wheel train.
 By dissecting the Octo Finissimo Chronograph GMT chronograph movement, it can be found that most of the movements use traditional constructions, which are not fundamentally different from traditional chronograph movements. But Bvlgari incorporated the edge automatic rotor into the chronograph movement, which greatly reduced the thickness of this watch, becoming the thinnest automatic chronograph in the world. In addition to Bulgari, like the Breguet’s 5377 ultra-thin self-winding tourbillon, Piaget’s 910P ultra-thin watches use edge automatic tourbillons to reduce the thickness of the watch. In recent years, Bulgari and Earl have competed fiercely in the ultra-thin field, and the court has resisted. Among them, the world’s thinnest manual chronograph is Piaget 883P, and the world’s thinnest automatic chronograph is Bulgari Octo Finissimo Chronograph GMT.

Parts of the Bulgari Octo Finissimo Chronograph GMT.
 Because Bulgari and Piaget both make jewelry, some players who are new to the world of watchmaking often regard them as pure ‘jewellery’ brands. In fact, each major brand has its own unique style and technology, each with its own strengths.