Sources
Where the facts come from
Every fact on this site was checked against these pages on 14 November 2026. We quote the article or catalogue body, not captions we cannot see, and we do not use Wikipedia.
- Encyclopaedia Britannica Scholars: gear, checked 14 November 2026
- Encyclopaedia Britannica: gear (mill caption), checked 14 November 2026
- Encyclopaedia Britannica Scholars: clock, checked 14 November 2026
- OpenStax, College Physics 2e, section 9.5 Simple Machines, checked 14 November 2026
- Science Museum Group: Model of Sun and Planet Gearing (Watt, 1782–1784), checked 14 November 2026
- Science Museum Group: Two heart wheels in gear transmitting a variable velocity ratio (Schröder, 1868), checked 14 November 2026
- Science Museum Group: Sturmey-Archer hub gear for cycles (1906), checked 14 November 2026
Drawings are our own, simplified and not to scale. This site is independent and is not affiliated with, or endorsed by, Encyclopaedia Britannica, OpenStax or the Science Museum Group.