In 1656, Pope Alexander VII had a problem familiar to anyone who has ever shared a room with a loud clock: he couldn’t sleep through the ticking. He commissioned the Campani brothers to build a timepiece that kept time silently, and they solved it by throwing out the part of the clock that makes the noise.
370 years later, maker Many Vices has rebuilt the mechanism in 3D-printed plastic, following the brass reconstruction that watchmaker Carlo G. Croce documented in a PDF and a series of videos.
Where the tick comes from
A conventional clock uses an anchor escapement. The escapement’s job is to release the gear train in measured increments so the hands advance at a constant rate rather than the weight simply unwinding. It does that by stopping and starting: a pallet catches a tooth, holds it, releases it, catches the next. Those impacts are the tick and the tock. The sound isn’t a side effect of a clock working — it is the clock working.
So a silent clock has to regulate the gear train without stopping it.
The crank escapement
The Campani solution was an eccentric crank escapement that provides continuous movement. Instead of arresting and releasing the train, it converts the drive into a smooth, constantly-in-motion regulation. Nothing catches, nothing impacts, nothing clicks.
Which raises the obvious question: why don’t all clocks work this way?
Because it’s inefficient. The crank escapement wastes a substantial share of the power coming off the weight and, as a direct consequence, gives much less runtime from the same drive. The anchor escapement won and persisted for centuries because the tick is cheap and the runtime is not — a reminder that in mechanism design, as in software, the ugly solution that conserves the scarce resource usually beats the elegant one that doesn’t.
Unless, of course, your client is a pope who can afford to have the clock rewound as often as it takes.
Why print it
Reproducing historical mechanisms in plastic has become one of the more genuinely useful things hobbyist 3D printing does. Brass reconstruction is a specialist craft with a long apprenticeship. Printing lets a mechanism be understood by being built, by people who will never cut a gear on a lathe, and it lets a design that survives in a handful of museum examples exist in as many copies as anyone wants.
There’s also a nice chain of transmission on display here: a 17th-century commission, a modern watchmaker’s brass reconstruction with published documentation, and now an extruded-plastic version anyone can watch run. That’s three technologies deep, and the middle link — Croce publishing his research rather than keeping it — is what made the third possible.