Roger Dubuis Excalibur Monobalancier Titanium
The Roger Dubuis Excalibur Monobalancier Titanium is the latest expression of Hyper Horology. A new addition to the Monobalancier collection, this latest model is housed in a 42mm titanium case and presented on a matching bracelet. Packed with technical refinements, this model also bears the prestigious Poinçon de Genève, providing independent assurance of its exalted creation.
Hyper Horology
Roger Dubuis is best known for making flying tourbillons and double flying tourbillons. However, its creative talents also extend to creating the ‘Knights of the Round Table’ models and the Quatuor, a watch endowed with four balances linked with five differentials.
Image – Roger Dubuis Excalibur DT RDDBEX0952
Last year, at Watches & Wonders 2022, Roger Dubuis, the prestigious marque synonymous with Hyper Horology, released a new version of the Excalibur Monobalancier, housed in EON gold. When contrasted with its siblings, the casual observer may assume this expression of RD ownership is comparatively pedestrian, however, nothing could be further from the truth.
Calibre RD720SQ (with micro-rotor)
Firstly, the Excalibur Monobalancier embraces complexity by incorporating a micro-rotor. Most automatic watches employ a large oscillating mass that sits above the movement, harvesting energy from the natural motion of the wearer’s wrist, energising the mainspring. Unfortunately, the addition of a conventional oscillating mass increases the thickness of a movement. Furthermore, a full-size oscillating mass would impair the view of the calibre and Roger Dubuis’ revered finishing. A micro-rotor surmounts the aforementioned issues while offering the convenience of automatic winding.
At this juncture, you may wonder why all automatic watches are not fitted with a micro-rotor, but incorporating this feature is not as simple as it sounds. The diminutive scale of a micro-rotor makes it difficult to generate sufficient inertia to energise the mainspring. Indeed, this technical obstacle has prevented all but a select number of Maisons from producing a viable micro-rotor.
With the advent of the Excalibur Monobalancier EON gold, the brand moved from an 18-carat gold rotor to a tungsten rotor, a material with a higher density. By making this change, the Manufacture has been able to increase inertia. With the EON gold model, the brand added some 18-carat pink gold accents to the micro-rotor for aesthetic reasons. However, with the new Roger Dubuis Excalibur Monobalancier Titanium the tungsten rotor is devoid of pink gold, reinforcing the model’s monochromatic theme.
Free-sprung balance
The Roger Dubuis Excalibur Monobalancier Titanium is also fitted with a free-sprung balance. With an index-regulated balance, the rate is adjusted by changing the effective length of the hairspring. However, with a free-sprung balance, the rate is adjusted by rotating inertia weights fitted to the balance wheel, altering the moment of inertia. This latter system takes longer to regulate, but it’s less susceptible to positional influence and the rate is less sensitive to shocks.
Furthermore, the inertia weights do not sit on the rim of the balance, but instead are positioned in-board, mitigating air perturbation and thereby, heightening precision.
Gear train
The gear train is responsible for transferring energy from the barrel to the escapement. Unfortunately, some of this energy is lost during this process due to frictional losses, etc. Roger Dubuis has expended much effort improving the efficiency of the movement, a factor that has contributed to the model’s 72 hour power-reserve.
Escapement
The firm has also used silicon for making various escapement components, including its unique escape wheel and curved pallets made from the glass-like material. Silicon (silicium) is not liable to corrosion, it’s lightweight, non-magnetic and friction-free; all useful attributes in watchmaking. Furthermore, silicon can be used to make intricate shapes not possible using traditional production techniques, a benefit the firm has fully exploited with the creation of the unusually shaped escape wheel and ingenious pallets.
When the Excalibur Monobalancier EON gold was launched, Gregory Bruttin, the brand’s Product Strategy Director, stated the new escapement was 20% more efficient than its predecessor and the balance wheel inertia had doubled, improving rate stability and reducing the regulating organ’s sensitivity to shocks.
Roger Dubuis Excalibur Monobalancier Titanium
The Roger Dubuis Excalibur Monobalancier Titanium is a new addition to the brand’s single balance portfolio of models. In many respects, it shares much in common with the Excalibur Monobalancier EON gold released in 2022. Indeed, it shares the same movement, the Calibre RD720SQ, and also bears the coveted Poinçon de Genève on its openworked torso.
Where this model differs from its older sibling is that it is presented in titanium. The brand does not specify which grade of titanium has been used, however, with a plethora of polished surfaces in evidence, it would suggest Grade 5 titanium has been employed. This metal is an alloy of titanium (90%), aluminium (6%) and vanadium (4%). Unlike cheaper Grade 2 titanium, Grade 5 is stronger and can be polished to a resplendent gleam. Both forms of titanium are lightweight, corrosion-resistant, weakly magnetic and hypoallergenic.
The disadvantage of using Grade 5 titanium is that it is incredibly expensive to machine. It is typically milled using a CNC machine. Its hardness wears out machining tools more readily and the milling speeds need to be reduced to avoid heat damage to the metal, making processing more protracted. Furthermore, due to its hardness, the metal is incredibly difficult to polish, a challenge the Maison has skilfully surmounted.
Closing remarks
Despite the various challenges of making a watch from Grade 5 titanium, especially to the Maison’s exalted standards, Roger Dubuis has not been deterred. The Excalibur Monobalancier Titanium is endowed with a lightweight case and, an equally complex, matching bracelet.
The brand has never shied away from technical challenges and continuously pursues perfection. This latest skeleton model brims with style, is simple to read and is beautifully finished. But most of all, its movement, the self-winding Calibre RD720SQ, wonderfully showcases the Manufacture’s incredible watchmaking know-how where even the minutest detail is executed to a matchless standard. Do you still think the Roger Dubuis Excalibur Monobalancier Titanium is a simple expression of Hyper Horology? Think again!
Further reading
Technical specifications
- Model: Roger Dubuis Excalibur Monobalancier Titanium RDDBEX0956
- Case: titanium, diameter 42 mm, water resistance 10ATM (100m), sapphire crystal to the front and exhibition case back.
- Functions: hours, minutes
- Movement: Calibre RD720SQ; self-winding movement; frequency 28,800 vph (4Hz), 32 jewels, power reserve 72 hours.
- Bracelet: titanium bracelet. Interchangeable with Quick Release System – QRS. Titanium triple folding, interchangeable with Quick Release System – QRS
- Price: £56,500 (RRP as of 4.5.2023)