Sinn 155 S Bright Star TEGIMENT® (155 S Revolution II)

Following the launch of our Sinn × The Rake & Revolution 155 Bundeswehr “Dark Star” in 2019, we have now created the Sinn 155 S Bright Star TEGIMENT® (155 S Revolution II), the first ever all-black execution in the history of the model as well as the first version with a TEGIMENT Technology case and sapphire crystal." WORDS BY CHERYL CHIA

At a certain juncture in the life of any watch enthusiast, especially amidst these times when demand vastly outstrips supply and there’s a race to the top in terms of prices, one may begin to question if the game is worth the candle. Suddenly, the whole pursuit appears not just costly, but also potentially driven by undue credulity, as the correlation between price and quality becomes increasingly blurred. But amidst this fatigue, there are watches that continue to uphold the essence of our passion, that continue to demonstrate how sophistication in design, engineering and execution, and even a hearty serving of history can be had without breaking the bank.

One brand that comes to mind is Sinn, whose utter disdain for any pretensions gives it an appeal that is hard to match. With watches such as the U1 and EZM series, it is hard not to admire the maturity and single-mindedness of the company in eschewing trends for brutal reliability and purpose, to say nothing of the wealth of technologies it has introduced such as TEGIMENT Technology hardening on its cases, Ar-Dehumidifying Technology that uses a combination of inert gas, copper sulfate capsules, and an Extreme Diffusion-Reducing (EDR) seal to prevent moisture ingress and condensation, and even a lubricant-free lever escapement, featuring synthetic diamond pallets known as DIAPAL.

When mechanical engineer Lothar Schmidt assumed control of the Frankfurt-based watch brand in 1994, he leveraged his technical expertise to introduce a string of innovative technologies to enhance the functionality of Sinn watches. The founder, the late Helmut Sinn, who passed away in 2018 at the age of 102, was a pilot who served in the Luftwaffe during the Second World War. He established his eponymous brand in 1961 at the age of 45, drawing upon his aviation experience from the outset to develop pilots’ chronographs and navigation cockpit clocks. Sinn later achieved a significant milestone by producing one of the earliest automatic chronographs used in space. The brand’s success enabled it to acquire assets from an ailing Breitling in 1979, including the rights to the Navitimer, and it even helped get a fledging Bell & Ross off the ground in 1992.

One of its most famous watches was the 155 Bundeswehr Chronograph. The watch was originally made by Heuer as the 1550 SG for the West German Federal Defence Force, i.e. Bundeswehr, from 1967 onwards. But in the ’80s, Helmut Sinn, who had his own ties to the military, purchased decommissioned watches from the inventories of the West German armed forces and sold these after refurbishing them. At the same time, he added the Sinn branding on the dial under the label “Bundeswehr Chronograph for Pilots.”

Today, as we introduce our latest collaboration with Sinn on the 155 S Bright Star TEGIMENT® (155 S Revolution II), we look back at the history of the model and take a deep dive into the watch, which is the first all-black execution as well as the first version with a fully TEGIMENT treated case.

The Sinn 155 S Bright Star TEGIMENT® (155 S Revolution II)

The new Sinn 155 S Bright Star TEGIMENT® (155 S Revolution II) is immediately distinguished from the original Bundeswehr Chronograph and its reissues as it is the first fully blacked-out version. Beyond its striking appearance, it is also the first in the history of the model to have a sapphire crystal and case treated with TEGIMENT Technology.

TEGIMENT Technology is a proprietary surface hardening treatment specifically developed by Sinn for its stainless steel watch cases and bracelets. While Sinn has not publicly disclosed the exact methodology behind the process, it involves a form of surface hardening that significantly increases the hardness and, consequently, scratch resistance of stainless steel. With a Vickers hardness of 1,200VH, TEGIMENT treated steel is five times harder than standard stainless steel and comparable to the high-tech ceramic used by Rado. But while ceramic is brittle and prone to fracture under excessive stress, TEGIMENT treated steel strikes a balance between hardness and toughness, providing enhanced durability and scratch resistance without sacrificing the material’s overall integrity.

TEGIMENT treated steel then undergoes an additional step of coating with Physical Vapor Deposition (PVD). Enhancing the surface hardness is essential to bolster the fatigue strength of the PVD coating. Traditionally, the significant and abrupt contrast in hardness between the PVD paint coating and the underlying steel poses a challenge, often resulting in cracking when subjected to stress. This occurs because the hard outer layer is seamlessly applied onto a much softer core. Upon sudden stress, the base material yields, failing to adequately support the outer layer and resulting in peeling or flaking. In contrast, TEGIMENT treatment brings the surface hardness of steel closer to the hard PVD coating, enabling it to support the coating far better.

The Bright Star has a modern screw-down caseback that has undergone TEGIMENT Technology hardening, along with the crown, pushers and bezel. Notably, while the original and all other re-editions were fitted with an acrylic crystal, the Bright Star has been upgraded with a sapphire crystal for superior scratch resistance. Additionally, in contrast to the 155 Bundeswehr “Dark Star,” which featured an anodized aluminum bezel with a “ghost” effect, the Bright Star has a TEGIMENT treated steel bezel with a black PVD coating, perfectly matching the case and dial.

The case maintains a diameter of 43mm, consistent with the original, and extends 51mm from lug to lug. As always, the effectiveness of a watch’s diameter isn't solely determined by numbers. The generous real estate has been put to good use; every element on the watch has a distinct and gratifying presence. In fact, the key factor that made the Bundeswehr Chronograph so appealing to start with was the balanced harmony among the various components: the proportions of the bezel, dial and hands, the size of the counters and the Arabic numerals.

Another attractive aspect of the Bright Star is the complete absence of vintage affectation. While custard-colored Super-LumiNova was selected to evoke the look of aged tritium on the Dark Star, the Super-LumiNova applied on the hands and the outsized Arabic numerals of the Bright Star is pure white for maximum contrast. The watch is named for the black Revolution star logo at six o’clock that has been treated with luminescent material, which emits a green glow in the dark.

Powering the watch is the aforementioned automatic Sellita SW510. It is based on the extremely robust and reliable Valjoux 7750, a proven performer that is widely acclaimed for its stable and high torque as well as balance power. Originally introduced in 1974 during the Quartz Crisis, the Valjoux 7750 was a technical achievement rather than artistic, which aligns with the expectations of a no-nonsense tool watch.

Like the 7750, the Sellita SW510 utilizes a triple layered cam system for coordinating the start, stop and reset, along with an oscillating pinion for coupling the main gear train to the chronograph mechanism. The running seconds hand is directly driven by the fourth wheel, which is constantly in contact with the oscillating pinion that is attached to a lever. When the chronograph is activated, it pivots, and the upper pinion engages the chronograph seconds wheel in the center above. While the Valjoux 7750 was designed with 6-9-12 counters, the minute recorder wheel was relocated from 12 to the three o’clock position in the Sellita SW510. It has a power reserve of >56 hours and a frequency of 4Hz.

As with the original, the 155 S Bright Star TEGIMENT® (155 S Revolution II) is fitted with a Bund-style leather strap. It also comes with a strap removal tool, spare spring bars as well as an additional black NATO strap. It is limited to 300 pieces and is available right now at a hard-to-argue price of USD 3600.

Technical specifications

Sinn 155 S Bright Star TEGIMENT® (155 S Revolution II)

Limited edition of 300 pieces

Case

• Material: Black TEGIMENT treated 904L steel
• Diameter: 43 mm
• Thickness: 14.75 mm
• Pilot's Bezel (Bi-directional)
• Glass: Sapphire crystal, anti-reflective on both sides
• Bezel, pushers and crown with Black Hard Coating (TEGIMENT Technology)
• Screw-down case back
• Water resistant to 100 meters

Dial and hands

• Black with luminescent Revolution star logo
• Super-LumiNova filled Arabic numerals
• Hands and indices in Super-LumiNova

Movement

• Chronograph mechanica SW510 calibre
• Self-winding movement
• Frequency: 28'800 vibrations per hour (4 Hz)
• Seconds stop function
• Power reserve of 56 hours

Functions/Indications

• Hours, minutes, seconds and chronograph

Strap and buckle

• Bund strap and additional nato strap

MSRP: USD 3'600 (excl. taxes)

For more information, please visit revolutionwatch.com