In his latest video, YouTuber Robert Murray-Smith shows how he constructed a gear train for a mechanical watch. The 3D model is available on Thingiverse and makes it possible to build a fully functional watch.
The focus is on the so-called “perpetual wedge”, a gear mechanism with a transmission ratio of 60:1, which corresponds exactly to the logic of a watch – 60 seconds equals one minute. By using a motor with 60 revolutions per minute and a clever gear design, seconds, minutes and hours are displayed precisely. The gearbox uses several levels of the perpetual wedge mechanism, supplemented by a cycloidal gear with a ratio of 12:1 to realize the hour movement. All parts can be produced on a 3D printer.
The construction involves a clever interplay of standard components and specially designed gears. The motor is inserted into a printed holder that can be adapted to different motor sizes. Bevel gears are used to adjust the direction of rotation of the gears so that all clock hands run correctly. The construction ends with a multi-layered mechanism that drives the second, minute and hour hands.
However, Murray-Smith points out that the clock is not designed for accuracy. The motor used is rated at 60 RPM, but without an electronic control, precise time setting is not possible. The lack of bearings also makes the mechanism relatively noisy.
Anyone interested in the replica can find the STL files for printing free of charge on Thingiverse.
Subscribe to our Newsletter
3DPresso is a weekly newsletter that links to the most exciting global stories from the 3D printing and additive manufacturing industry.
