Bastien Jaffré - Founder of Mercier & Fils

Background

Mechanical watchmaking isn't a market you enter by accident. Bastien Jaffré came to it through obsession: understanding why an automatic watch left on a poorly calibrated winder eventually stops, and what that actually costs a precision caliber.

Before founding Mercier & Fils, he spent several years documenting the technical specifications of major manufactures - Rolex, Audemars Piguet, Patek Philippe, Omega, Vacheron Constantin - cross-referencing service manuals, maintenance sheets, and empirical amplitude bench tests. This groundwork, built reference by reference, has grown into a database now listing over 5,800 watch references covering 86 brands, with more than 200 caliber and variant designations listed.

Mercier & Fils was born from a simple observation: the luxury watch winder market lacked technical rigor. Plenty of beautiful products, very little reliable information on TPD, rotation direction, or power reserve. Bastien set out to build a house that takes these parameters seriously - in its products as much as in its content.

The Mercier & Fils Journal is the editorial extension of that standard. Every article follows the same protocol: cross-verification of technical data (manufacturer documentation, bench testing, multi-source cross-checking), writing, then a personal review by Bastien before publication. No figure - TPD, power reserve, EN 1143-1 grade, balance wheel amplitude - is published without being verified at the source.

Areas of Expertise

• Automatic winding Rotor mechanics, activity and rest cycles, differences between unidirectional and bidirectional winding calibers. Why a winder should never run continuously.
• TPD - Turns Per Day Calculation, manufacturer- and caliber-specific settings, common mistakes. Reference values for Rolex (650 BOTH), Patek Philippe (800 CCW), Audemars Piguet (varies by caliber), Omega, and Vacheron Constantin.
• Power reserve & calibers Impact of insufficient TPD on power reserve, resetting complications after a stoppage, balance wheel amplitude as an indicator of a caliber's health.
• Safe security - EN 1143-1 standard Grade 0 to Grade VI classification, resistance units (RU), partial and total access testing, correlation with insurance coverage limits. How to read a certification plate.
• Preserving collector's watches Storage conditions, humidity, magnetic shocks, the effects of overwinding on watchmaking oils, choosing a safe with integrated winders for a diversified collection.

Journal Articles

Technical guides, comparisons, and editorials written and validated by Bastien Jaffré.

Editorial Transparency Note

The Mercier & Fils Journal uses AI-assisted editorial tools for research, structuring technical data, and drafting the first version of articles. These tools speed up information gathering and cross-source consistency checks.

Every article then follows a four-step human validation protocol:

1. Technical data verification at the primary source (manufacturer documentation, service sheets, chronometry certificates).
2. Multi-source cross-checking for every published figure - TPD, power reserve, EN 1143-1 grade, amplitude.
3. Final review and approval by Bastien Jaffré before publication.
4. Regular updates to articles as manufacturer specifications evolve or new data becomes available.

No Journal article is published without this human validation. The last-updated date is shown at the top of every technical guide.