What Is the CP-02?
The CP-02 is a mechanical watch with something no other timepiece at its price point offers: movement bridges machined from carbon fiber reinforced polymer (CFRP). Built by Hirotaka Sugiyama, a formally trained watchmaker with 20 years of professional experience, the CP-02 replaces the main bridge structure, train wheel bridge, and balance cock of an ST3600 manual-wind movement with components he designed, machined, and finished in his workshop in Osaka, Japan.
It is not a movement built from scratch. It is something arguably more interesting: a hybrid that questions whether the materials we’ve used inside mechanical movements for over a century are the only ones that work.
The watch delivers over 50 hours of power reserve, keeps time within +10 seconds per day, and is planned for limited production at approximately $7,500 – a price point that sits well below the six-figure watches from Richard Mille and Roger Dubuis that have previously experimented with carbon composites in movement components.
Why Isn’t Carbon Fiber Used Inside Watch Movements?
Carbon fiber is everywhere in modern watchmaking, but only on the outside. Cases, bezels, dials, and straps made from CFRP have become standard across brands from entry-level to haute horlogerie. The material’s appeal is clear: exceptional strength relative to its weight, a visually distinctive weave pattern, and associations with motorsport and aerospace.
But inside the movement, where gears mesh, jewels sit in their settings, and springs store and release energy across tens of thousands of cycles per day, the industry has relied on brass, steel, nickel silver, and occasionally titanium or German silver. The reasons are real. Movement components demand extreme dimensional precision, often measured in hundredths of a millimeter. They need to resist wear over years of continuous operation. They must hold jewel bearings securely. And they need to be serviceable decades into the future.
CFRP presents specific challenges at this scale. Unlike metal, it’s an anisotropic composite – its properties differ depending on which direction you measure them, because the material’s strength comes from the orientation of fibers within a resin matrix. Machining it means cutting through both fibers and resin simultaneously, creating failure modes like delamination, fiber pullout, and poor edge quality that don’t exist in metalworking.
These are solvable problems. But until Sugiyama, almost nobody was trying to solve them.
Who Is Hirotaka Sugiyama?
Hirotaka Sugiyama is a professionally trained watch technician based in Osaka, Japan, with approximately 20 years of experience in mechanical watch repair, overhaul, quality control, and assembly. His CFRP development work is a personal project pursued independently alongside his professional career.
His path to building a carbon fiber watch movement wasn’t a straight line. As a university student in Japan, he studied polymers and conducted research on resin materials – not specifically CFRP, but enough to build a foundational understanding of composite behavior. He was also a competitive cyclist who rode a carbon fiber road bike, giving him a tactile sense of what the material could do as an engineering structure.
After university, he entered the watch industry and spent two decades working with mechanical movements. That combination – polymer science, physical experience with carbon fiber, and deep watchmaking expertise – eventually converged into a single question that became his research project: if carbon fiber is such an effective structural material, why isn’t it used inside mechanical watch movements?
His previous project, CP-01, was featured by CompositesWorld, a respected composites industry publication, validating his work from the materials engineering side.
From CP-01 to CP-02: What Failed and What Worked
CP-01 was the proof of concept. It used an all-CFRP bridge structure and demonstrated that carbon fiber could function as a structural material inside a mechanical watch movement. But it also exposed the limits of going all-in on CFRP.
The main issues were long-term wear and serviceability. CFRP excels as a structural material – stiff, light, and strong – but it’s not ideal for every contact surface inside a movement. Areas subject to repeated friction and zones around bearing points, where jewels need to be held with absolute precision, presented problems that an all-CFRP approach couldn’t resolve elegantly.
This is where Sugiyama’s two decades of watchmaking experience proved as valuable as his materials knowledge. A pure engineer might have tried to solve every problem with better CFRP formulations. A watchmaker who has spent years seeing where movements actually fail knows that some problems are better solved by choosing the right material for each specific function.
CP-02 is the result: CFRP where the material’s characteristics provide genuine advantages, and metal where durability and serviceability matter more. The development took approximately 18 months of repeated CNC machining, assembly, functional testing, adjustment, and design modification. Rather than building complete prototype movements, Sugiyama iterated on individual components, remaking some parts many times before achieving satisfactory performance.
How the CFRP Movement Bridges Are Made
Sugiyama machines all CFRP movement components in his own workshop using a modified Genmitsu CNC1610 – a hobbyist-grade desktop CNC router that retails for roughly $200 – fitted with an upgraded 300W spindle and GRBL control software.
For context: major watch manufacturers machine movement components on Swiss-made CNC equipment costing hundreds of thousands of dollars. Sugiyama achieves movement-component tolerances on a machine that costs less than a strap from many luxury watch brands.
The tooling illustrates how demanding this work is. He uses 0.5mm end mills – tools with a cutting diameter roughly five times the width of a human hair – specifically designed for CFRP machining. At this scale, tool deflection and breakage are constant challenges. The anisotropic nature of CFRP means that fiber orientation, delamination risk, and edge quality must be managed simultaneously while maintaining the extremely tight dimensional tolerances a mechanical movement demands.
Which components are CFRP and which stay metal? The main plate and bridge structure, train wheel bridge, and balance cock are machined from CFRP. Metal is retained where the winding stem makes contact (a high-friction interface), in the supports for the crown wheel, ratchet wheel, and click spring, and crucially, in the jewel bearing seats. Sugiyama uses press-fitted metal bushings to secure the jewels in the train wheel bridge rather than setting them directly into the CFRP. “It is possible to press-fit the jewels directly into CFRP,” he notes, “but metal bushings provide stronger and more secure positioning both horizontally and vertically.”
The CFRP case is the only component not made in-house; Sugiyama has manufacturing partners for that, along with the dial and hands. For the movement, he personally handles machining, finishing, assembly, functional testing, and adjustment.
CP-02 Specifications and Performance
| Specification | Detail |
|---|---|
| Base caliber | ST3600 (manual wind) |
| CFRP components | Main plate/bridge, train wheel bridge, balance cock |
| Power reserve | 50+ hours (measured) |
| Daily rate | Approx. +10 seconds/day |
| Positional variation | Approx. 12 seconds |
| Frequency | 21,600 vph (3 Hz) |
| Jewels | 17 |
| Case material | CFRP with metal threaded bushings |
| Dial | CFRP, minimal design |
| Case construction | 4-screw middle case to caseback |
| Crystal | Exhibition caseback |
| Strap | Black leather, croc pattern |
These numbers demonstrate that the CFRP bridge structure doesn’t compromise the movement’s core function. Performance is comparable to a stock ST3600.
An intriguing preliminary finding: the CFRP balance cock appears to show smaller rate changes under vibration compared to the conventional metal balance cock. Sugiyama is careful to mark this as unconfirmed. “To present this as a reliable technical characteristic, I need to conduct repeated measurements using the same movement and standardized vibration conditions,” he says. That kind of intellectual honesty – flagging a potentially exciting result as unproven rather than marketing it as a feature – reflects how Sugiyama approaches his work.
Design Philosophy: Why the Dial Is Blank
The CP-02’s dial side is strikingly minimal. No indices. No brand name. No minute track. Just a CFRP dial with two small gold dot markers and a pair of gold dauphine-style hands.
“The main focus of the CP-02 is the mechanical structure, particularly the CFRP movement visible through the caseback,” Sugiyama explains. “Rather than adding a lot of information to the dial, I wanted to create a contrast: a very minimal front side and a technically complex mechanical movement visible from the back.”
The case reinforces this. The CFRP middle case is secured to the caseback with four exposed screws – not as an aesthetic choice, but as an engineering necessity. Threads cannot be cut directly into CFRP, so Sugiyama press-fits and bonds threaded metal bushings into the carbon fiber structure. The industrial look is a byproduct of honest construction.
Flip the watch over and the exhibition caseback reveals the real story: the dark CFRP mainplate with its distinctive carbon weave texture, brushed steel gear caps, gold-toned wheels, and ruby jewels. The visual contrast between the matte carbon and traditional watchmaking elements is what the hybrid architecture makes possible.
Price, Production, and What’s Next
Sugiyama plans to produce the CP-02 in limited quantities of approximately 10 to 20 watches per year at a target price of around $7,500 (approximately 1.2 million yen). He intends to personally handle assembly, adjustment, and quality control.
He has manufacturing partners for the case, dial, hands, and CFRP movement components, giving him a production structure that could support larger volumes. But the priority is keeping the work close. “If the business grows to the point where I can no longer personally handle assembly, adjustment, quality control, and sales, I would consider bringing additional people into the workshop.”
Beyond CP-02, Sugiyama is developing a retrograde mechanism as a separate project, currently in the testing and refinement stage. He’s also exploring titanium components and developing his own mechanical modules beyond the CFRP focus.
FAQ: Carbon Fiber in Watch Movements
CFRP is widely used in watch cases, bezels, and dials, but its use as a structural material inside mechanical movements is extremely rare. Richard Mille and Roger Dubuis have used carbon composites for some movement components in six-figure timepieces. Sugiyama’s CP-02 is notable as an independent project that replaces multiple movement bridges with CNC-machined CFRP at a fraction of the price.
The CP-02 is based on the ST3600, a manual-wind caliber derived from the ETA 6497 architecture. Sugiyama replaced the main bridge structure, train wheel bridge, and balance cock with his own CFRP components while retaining metal in high-friction and bearing areas.
The CP-02 achieves approximately +10 seconds per day with a maximum positional variation of about 12 seconds, comparable to stock ST3600 performance. Preliminary testing suggests the CFRP balance cock may offer improved stability under vibration, though Sugiyama considers this finding unconfirmed.
The CP-02 is planned for limited production of 10-20 pieces per year at approximately $7,500 USD.
All CFRP movement components are machined by Hirotaka Sugiyama in his workshop in Osaka, Japan, using a modified desktop CNC router with 0.5mm CFRP-specific end mills.
The CP-02 delivers over 50 hours of measured power reserve, exceeding the typical ST3600 specification.
Photos and build process images courtesy of Hirotaka Sugiyama.