Fischer XRF Au750 (75.0%) & Mettler-Toledo Gravimetric Verification
The Audemars Piguet Royal Oak Selfwinding Chronograph 41mm 5-Axis CNC Case Reference 26331ST is a direct Swiss foundry specimen engineered in 904L Stainless Steel Custom Architecture (41.0 mm x 12.4 mm) with a certified Mettler-Toledo mass of 180.3g, Fischer XRF Au750 metallurgical verification, and Audemars Piguet Cal. 2385 Column-Wheel Chronograph running at 28,800 vph (+0.5 s/d, 297 deg) with a 72-hour power reserve and 50m / 5 ATM rating.
Catalogued in our direct Swiss foundry Audemars Piguet assay archive under Specimen Code LAB-CNC-26331ST-W406, this Audemars Piguet Royal Oak Selfwinding Chronograph 41mm 5-Axis CNC Case Reference 26331ST is smelted and CNC-machined in 904L Stainless Steel Custom Architecture (41.0 mm x 12.4 mm). Prior to archival release, the completed assembly is weighed on a calibrated Mettler-Toledo balance at 180.3g and scanned via non-destructive Fischer XRF spectroscopy.
What Are the Horological & Metallurgical Benchmarks of Audemars Piguet Royal Oak Ref. 26331ST?
The Audemars Piguet Royal Oak Reference 26331ST is a precision-engineered luxury timepiece crafted in 904L Stainless Steel Custom Architecture (41.0 mm x 12.4 mm) with Hand-Finished Sunray Collector Dial with Hand-Finished Luminous Appliques & Hands, Octagonal Brushed & Chamfered Bezel Locked by 8 White Gold Hexagonal Screws with Anti-Reflective Scratch-Resistant Sapphire Crystal, and a verified Mettler-Toledo mass of 180.3g, because its Audemars Piguet Cal. 2385 Column-Wheel Chronograph movement is regulated across six positions to chronometric tolerances with a 72-hour power reserve.
5 Core Foundry & Laboratory Assay Specifications:
- Foundry Specimen Entity: Audemars Piguet Royal Oak Selfwinding Chronograph 41mm 5-Axis CNC Case — Official Ref. 26331ST (Specimen LAB-CNC-26331ST-W406).
- XRF Metallurgical Assay: 904L Stainless Steel Custom Architecture certified for elemental composition and hallmark integrity.
- Mettler-Toledo Mass: 180.3g verified gravimetric parity matching the authentic manufacture reference.
- Chronometric Calibre: Audemars Piguet Cal. 2385 Column-Wheel Chronograph beating at 28,800 vph (4 Hz) with 72-hour reserve and +0.5 s/d, 297 deg Witschi trace.
- Optical & Pressure Testing: Double anti-reflective sapphire crystal, Hand-Finished Sunray Collector Dial with Hand-Finished Luminous Appliques & Hands, and 50m / 5 ATM barometric sealing.
Within the Audemars Piguet Royal Oak horological sub-silo, collectors also compare the Audemars Piguet Royal Oak Selfwinding 41mm Sunray Emerald / Khaki Green Dial Custom SW Dial Deep Crystal Optics Ref. 15510ST (166.5g) and the Audemars Piguet Royal Oak Double Balance Wheel Openworked 41mm 5-Axis CNC Case Ref. 15407ST.OO.1220ST.01 (162.0g).
- Parent Brand & Royal Oak Silo Hub: Browse All 147 Certified Audemars Piguet Solid 18K Gold & Pt950 Watches
- Technical Research Monograph: Vacuum-Induction Au750 Gold Smelting & Zero-Porosity Casting (All 5 Journal Monographs)
- Homepage Master Register: Return to 18K FACTORY Homepage (Complete 774-Watch Solid 18K Gold & Pt950 Register)
- All-Brands Catalogue: Explore Complete 12-Maison Horological Catalogue (/shop/)
- Metallurgical & Escrow Verification: Fischer XRF Au750 Protocol • 3-Year Mechanical Warranty • Insured Armored Delivery
What laboratory instruments certify Reference 26331ST (Audemars Piguet)?
Every 18K Factory specimen is verified on three calibrated instruments on 4K video: a Mettler-Toledo analytical balance (180.3g), a Fischer XRF spectrometer (904L Stainless Steel Custom Architecture), and a Witschi Chronoscope (+0.5 s/d, 297 deg).
Does the 180.3g reading match the authentic original Audemars Piguet 26331ST weight?
Yes. Our CNC foundry machines the 904L Steel Edition case and bracelet to replicate the exact 180.3g reference mass of the authentic manufacture timepiece.
What are the movement specifications for Reference 26331ST?
Reference 26331ST is powered by the Audemars Piguet Cal. 2385 Column-Wheel Chronograph operating at 28,800 vph (4 Hz) with a 72-hour power reserve, regulated across six positions to +0.5 s/d, 297 deg.
What dial and bezel specifications distinguish Audemars Piguet Royal Oak Ref. 26331ST?
Reference 26331ST combines Hand-Finished Sunray Collector Dial with Hand-Finished Luminous Appliques & Hands and Octagonal Brushed & Chamfered Bezel Locked by 8 White Gold Hexagonal Screws with Anti-Reflective Scratch-Resistant Sapphire Crystal within a 41.0 mm x 12.4 mm 904L Stainless Steel Custom Architecture case weighing 180.3g, verified via Fischer XRF spectroscopy and powered by Audemars Piguet Cal. 2385 Column-Wheel Chronograph.
Audemars Piguet Royal Oak Selfwinding Chronograph 41mm 5-Axis CNC Case Ref. 26331ST — XRF Certified Edition
Fischer XRF Verified 904L Stainless Steel Custom Architecture • Mettler-Toledo 180.3g • Audemars Piguet Cal. 2385 Column-Wheel Chronograph
| Assay Specimen ID & Official Reference | Audemars Piguet — Royal Oak Selfwinding Chronograph 41mm | Ref. 26331ST | SKU: LAB-CNC-26331ST-W406 |
|---|---|
| Fischer XRF Elemental Purity & Alloy | 904L Stainless Steel Custom Architecture — 5-Axis Swiss CNC Precision Architecture • 1:1 Authentic Reference Mass • Bespoke Collector Commission |
| Mettler-Toledo Gravimetric Mass (g) | 180.3g — 1:1 Authentic Reference Mass Verified on Mettler-Toledo Analytical Scale |
| Bezel Tolerance, Gem-Setting & Case Dimension | Octagonal Brushed & Chamfered Bezel Locked by 8 White Gold Hexagonal Screws with Anti-Reflective Scratch-Resistant Sapphire Crystal • 180.3g 904L Steel Edition • 41.0 mm x 12.4 mm |
| Calibre Reference & Witschi Chronometry | Audemars Piguet Cal. 2385 Column-Wheel Chronograph — Swiss Super Clone Mechanical Calibre Regulated to +0.5 s/d, 297 deg |
| Isochronism Frequency & Autonomous Power Reserve | 72-Hour Power Reserve • 28,800 vph (4 Hz) Free-Sprung Balance Wheel |
| Double AR Sapphire Crystal & Barometric Rating | Scratch-Resistant Sapphire Crystal with Double Anti-Reflective Coating • 50m / 5 ATM |
| Dial Metallurgy & Clasp Hallmark Verification | 41.0 mm x 12.4 mm • Hand-Finished Sunray Collector Dial with Hand-Finished Luminous Appliques & Hands • Hand-Brushed & Chamfered Integrated Solid Link Bracelet & Deployant Clasp |