Armin Strom One Week Titanium Skeleton Watch Review
Unveiled at Watches & Wonders 2025, the Armin Strom One Week Titanium Skeleton is housed in a 41 mm case, formed of Grade 5 titanium, and comes presented on a matching bracelet. Upholding the brand’s proven ‘we show what we make’ philosophy, the watch unites cutting-edge know-how with no-compromise hand craftsmanship. The resultant timepiece is a pure, ultra-refined composition likely to seduce most horophiles and even some unsuspecting watch journalists.
Skeleton Watches
If you meet an architect unable to understand the game of Jenga, then I suggest you refrain from asking them to design your dream home. While a building may look attractive, if its structure is inherently weak, it will undoubtedly be unsuitable for habitation. Indeed, a viable structure must be intrinsically strong and rigid. The same is true for a watch movement.
Over the years, watchmakers have sought to skeletonise movements, keen to expose an array of components often hidden from view with a conventional watch. However, when paring back a movement in the pursuit of style, consideration must also be given to solidity and stiffness. A movement that has a tendency to flex may impair the efficiency of the gear train or stop altogether. Moreover, the overzealous removal of metal can, in extremis, cause a mainplate or bridge to deform.
André-Charles Caron (1698-1775)
Skeleton watches date back to the 1760s with the first example crafted by French clockmaker, André-Charles Caron (1698-1775). Using a ‘regular’ movement as the basis for a skeleton watch, the craftsperson would map out a design and begin drilling a series of holes in the movement structure. Thereafter, they would feed a handsaw blade through each aperture and carefully cut the bridges and mainplate. During this process, it was essential that the blade remained perpendicular to the surface, taking great care not to cut surfaces at an angle. Once all incisions were made, the surfaces would then be drawn out to remove any burrs or evidence of cutting. Finally, the bridges and mainplate were refined with bevelling and various forms of decoration.
Openworking watch movements
Openworking a movement is not a job for amateurs. Due consideration must be given to the smooth motion of parts and the overall reliability of the watch. For example, jewel beds, screws and the areas neighbouring the gear train pivots must remain untouched. Moreover, the movement’s overall torsional rigidity must always be considered; remember, solidity and stiffness are essential.
Mr Armin Strom began skeletonised watches in 1967
In 1967, Mr Armin Strom, a retailer of clocks with a penchant for restoration, began skeletonising watches. This involved removing parts of the movement that were superfluous to its operation. Visitors to Strom’s shop in Burgdorf could witness the watchmaker at work, paring back movements with an inordinate amount of skill. Eventually, Strom’s work came to the attention of several watch brands, leading to him being commissioned to make limited numbers of skeletonised watches.
Armin Strom Manufacture opened in 2009
In 2006, Mr Strom established a limited company bearing his name, Armin Strom AG. Eventually, this company was acquired by Serge Michel and, in 2009, together with his longtime friend and master watchmaker, Claude Greisler, the young company established a new Manufacture in Biel. Following the financial crisis of 2008, the new company was able to procure cutting-edge equipment at keen prices. This provided the firm with the means to make its own in-house movements.
With the necessary equipment and much in-house expertise, the Maison released a plethora of calibres, each skeletonised and engineered to the nth degree. Indeed, for many years the company’s strapline was ‘we show what we make’.
Most notably, these contemporary creations featured mainplates and bridges that were skeletonised from the outset. Rather than adapting what had gone before, Greisler and his team used modern CAD systems to design new calibres endowed with optimised architecture. The forces acting on each part of the movement could be calculated precisely, allowing them to create openwork, beam-like structures safe in the knowledge that they were strong and rigid. Furthermore, using a combination of CNC, wire erosion and bar turning machines, parts could be produced to infinitesimal tolerances, often measured in microns. The days of handsaws were over.
Armin Strom One Week – first movement in-house movement (2010)
Armin Strom released its first movement, the Calibre ARM09, in 2010. It formed the basis of the One Week collection, a series of models referencing different elements eg water. Featuring two barrels, a small seconds indication and a power-reserve indicator, the watches revealed many components dial-side for the delectation of owners. As the collection name implies, these models had a prodigious power-reserve of 7 days.
Armin Strom One Week Manufacture Edition (2024)
Last year, the Biel-based firm released the ‘One Week Manufacture Edition‘, a modern take on the aforementioned 2010 reference. Housed in a 41 mm steel case, it featured a new mechanical heart, the hand-wound Calibre ARM21. This watch, limited to 100 pieces, was the inaugural version of the new generation One Week. Now, the latest expression of the new generation One Week, the Armin Strom One Week Titanium Skeleton joins the brand’s extensive portfolio of products.
Armin Strom One Week Titanium Skeleton (2025) – Grade 5 titanium
Recently unveiled at Watches & Wonders 2025, the Armin Strom One Week Titanium Skeleton eschews stainless steel in favour of the eponymous ultra-light alloy. Grade 5 titanium, not to be confused with cheaper Grade 2 titanium, is composed of 90% titanium, 6% aluminium, 4% vanadium and minuscule traces of iron and oxygen. As well as having a low mass, it is strong, not liable to corrode, anti-magnetic and hypoallergenic; all useful attributes for a watch.
However, Grade 5 titanium, due to its inherent strength, is challenging to machine. The protracted creation of parts heightens cost, leading to several brands treating it almost as a noble metal. In my experience, a watch formed of Grade 5 titanium delivers a superior wearer experience than that of steel. Armin Strom has not only used the material for the case, it has also chosen to equip the new One Week with a beautifully engineered titanium bracelet.
Armin Strom One Week Titanium Skeleton – front of house
Front of house, besides indicating the hours, minutes and seconds, the wearer is indulged with glorious views of movement components in motion, both mainsprings in various states of tension and supreme finishing.
Armin Strom One Week Titanium Skeleton – views to the rear
To the rear of the watch, a pane of sapphire crystal grants sight of the escape wheel cock, pallet lever in motion and the variable-inertia balance. This latter feature confers superior precision when compared with the usual index-regulated balance. Moreover, note that the inertia screws which alter the rate of the movement are recessed within the rim of the balance wheel. This helps mitigate air turbulence, augmenting isochronism. Although a small detail, it is indicative of the Manufacture’s near-obsessive quest for perfection.
Armin Strom One Week Titanium Skeleton – closing remarks
A function of my job is that I frequently fall in love with watches, but for financial reasons I have to curtail my horological acquisitiveness. Indeed, I own very few watches. However, many moons ago, I succumbed to the charms of a beautiful Armin Strom Gravity Water, a watch I continue to cherish.
While the brand from Biel seduced me all those years ago, I have to say, objectively, its watches are now better than ever. The designs are cleaner and sharper, the cases are more comfortable to wear and the finissage is superior. Indeed, when you reflect on the history of Armin Strom, it has advanced the notion of skeletonising watches, abandoning the idea of modifying movements and bridges solely with drills and hand saws, instead favouring cutting-edge technology and employing rare expertise. Quite simply, strength and rigidity have never been so good.
Further reading
Technical specification
- Model: Armin Strom One Week Titanium Skeleton
- Reference: TI25-OW.75
- Case: Grade 5 titanium, diameter 41.00 mm, height 10.60 mm, water resistance 10 ATM (100 metres), sapphire crystal to front, exhibition case back.
- Functions: hours, minutes, small seconds
- Movement: Caliber ARM21-S, hand-wound movement, frequency 25,200 vph (3.5 Hz), 35 jewels, power reserve 7 days, 194 components.
- Bracelet: titanium with a double folding clasp
- Price: CHF 39,000 – (RRP as of 20.4.2025)
- Limited Edition: 100 pieces