“Retrograde” describes the clock’s hands moving along limited arcs, then returning to their starting positions—not spinning backward continuously. In this laser-cut biretrograde design, separate hour and minute indicators make that arc-and-return motion using cams on a common clock movement.
What does “retrograde” mean in a clock?
A conventional clock hand circles the dial continuously. A retrograde indicator instead travels across a limited arc and then returns to its starting point. The return is part of the motion; it is not a hand rotating backward around the dial.
This project is called biretrograde because it has two such indicators: one for hours and one for minutes. A separate 2022 Hackaday feature describes the same broad arc-and-return idea in a different, 3D-printed clock, but that is not the mechanism or build covered here: Hackaday’s 2022 retrograde clock.
How does this laser-cut clock make its indicators move?
Hackaday’s November 26, 2025 account of PaulH175’s Instructables project describes a pair of cams mounted on the hour and minute shafts of a common clock mechanism. As those shafts turn, the cams lift and lower the indicator arms. Gearing at the arms’ pivots translates that cam-controlled movement into the visible hand motion. The result is an arc followed by a return, rather than a full circular sweep.
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The project uses laser-cut parts, and Hackaday reports that SVG files are available on the linked Instructables project page. Consult the project itself for the current files and full assembly details; the reporting does not establish a specific movement model or the dimensions needed to select one.
What should you check before building one?
Match the clock movement to the design
“Quartz clock movement mechanism” is a useful phrase when looking for the kind of component described, but it is not a confirmed model recommendation. Before buying, compare the project files and instructions with the movement’s shaft geometry, mounting arrangement, and the thickness of the clock face or material the shaft must pass through. Those compatibility specifications are not stated in Hackaday’s account.
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