This is part of my new project and book Watchmaking with Python
Mechanical watchmaking has evolved far beyond traditional design methods. Today, numerical simulation, data analysis and software engineering have become essential tools in the development of high-performance mechanical movements.
Python for Watchmaking bridges the gap between classical horology and modern engineering. Using practical Python examples, the book demonstrates how physical principles can be modelled, analysed and optimised with professional software tools.
The book is available in English, German and French, making it accessible to readers throughout the international watchmaking industry.
The book covers a wide range of engineering topics, including:
- Python programming for engineering applications
- Mechanical watch theory
- Gear trains and escapements
- FFT analysis of timing variations
- Dynamic balancing
- Hertzian contact pressure
- Signal processing and data analysis
- Design of Experiments (DOE)
- Monte Carlo simulation
- Reliability and Weibull analysis
- Silicon hairprings
- Numerical optimisation
- Modern graphical user interfaces with PyQt
- Automatic report generation
- Engineering software architecture
➡️ Available here: watchmaking
Professional analysis tools for Swiss watch gear trains.
The Watchmaking Gear Simulator is a collection of applications for analysing, editing and converting traditional watch wheel and pinion profiles based on the Belot geometry format.
The software has been developed with a strong focus on practical watchmaking applications, including contact analysis, efficiency calculations, Hertzian pressure, manufacturing tolerances and CAD integration.
- Graphical contact analysis
- Active contact zone calculation
- Gear mesh efficiency
- Torque ripple analysis
- Hertzian contact pressure
- Contact window calculation
- Wheel and pinion drive simulation
- Contact path visualisation
- Monte Carlo tolerance simulation
- Batch processing
- Automatic PDF reports
- SVG and PNG graphics export
- Fusion 360 MCP export
The Profile Editor allows direct modification of Belot gear profiles.
Features include:
- Interactive profile editing
- Wheel and pinion support
- Profile mirroring
- Contact analysis comparison
- Material selection
- Immediate simulation of edited geometry
The Converter supports conversion between different watch gear profile formats.
Supported formats include:
- Belot TXT
- DXF
- ENO
- EGR
- NIHS 20-30
The converter preserves the original geometry whenever possible and supports exact arc and line reconstruction.
The NIHS Generator creates standard NIHS 20-30 watch gear profiles.
Features include:
- Wheel generation
- Pinion generation
- Automatic Belot export
- Direct compatibility with the Gear Simulator
This repository also includes the complete source code of
The parser demonstrates how Belot profile files are read and interpreted.
It is intended as a reference implementation for developers who want to
- read Belot files
- build their own applications
- generate custom profiles
- integrate Belot geometry into CAD or CAM software
Precompiled applications are available for:
- Windows 11 (64-bit)
- macOS (Apple Silicon)
The macOS applications are digitally signed.
Download the latest release from the Releases section.
Unzip the package.
Start the desired application:
- Watchmaking Gear Simulator
- Profile Editor
- Profile Converter
- NIHS Generator
No Python installation is required.
- Generate or import wheel and pinion profiles.
- Inspect and edit the geometry.
- Run contact analysis.
- Evaluate efficiency and Hertzian pressure.
- Perform Monte Carlo tolerance simulations.
- Export geometry for Fusion 360.
Additional documentation, tutorials and theory papers are available in the project documentation.
The generated PDF reports explain the calculated results in detail.
The applications are distributed as freeware binaries.
The included parser source code is released under the MIT License.
Please see the LICENSE file for details.
The Watchmaking Gear Simulator is developed as an open-source project and is available free of charge for private, educational and commercial use.
If you or your company benefit from this software, please consider supporting its continued development through GitHub Sponsors.
Your sponsorship helps fund new features, testing, documentation and long-term maintenance.
Bug reports and feature suggestions are always welcome.
If you discover incorrect geometry, unsupported profile formats or calculation issues, please open an Issue.
Contributions improving documentation are also appreciated.
The software is intended for engineering, educational and research purposes.
Although every effort has been made to verify the calculations, users remain responsible for validating results before applying them to production components.
The project builds upon many years of practical experience in Swiss watchmaking, gear geometry and escapement development.
Special thanks to everyone who has provided valuable feedback during testing.
- Gear Simulator
- Contact Analysis
- Monte Carlo Simulation
- Profile Editor
- Converter
- Fusion Export
(Add example images here.)
- Escape wheel
- Fourth wheel
- Third wheel
- Centre wheel
- Pinion profiles
- NIHS examples
Questions, suggestions and bug reports are welcome through the GitHub Issues page.