Clock with Perpetual Calendar

Perpetual calendar is one of the representative mechanism of complication clocks and watches. It shows correct date up to 2099 without correction because it can handle all kind of month lengths including February of leap years.

Note

New version driven by a quartz clock movement is released.
https://www.thingiverse.com/thing:5980536

Multi language versions of subdials are at
https://www.thingiverse.com/thing:5986655

Features

• Mechanical perpetual calendar which is only seen on very expensive watches and clocks
• This clock has four sub-dials to show 24hours, month, date and day of the week
• Ready for practical use. The clock itself is driven electrically and more accurate than mechanical one. No winding necessary
• Easy calendar adjustment by direct manipulation of hands

Design highlights

• Four sub dials are arranged regularly
• All six hands rotate CW
• Skeleton design to maximize the visibility of the mechanism
• No bearings or metal shafts are used but works smoothly
• No screw heads in front
• You do not need supports in 3D print
• Printable with relatively smaller printers including Prusa MINI (size of maximum part is 180 x 180mm)

To design the gears, I used "Precision Gears" addon for Blender,
https://makertales.gumroad.com/l/PrecisionGears

Note Feb 26, 2023: The calendar proceeds to the next day around 10:30-11:00 at night. You can see the motion at that time, however, it might be confusing at midnight. To avoid this problem, attach the main cam at the bottom ("24h-gear.stl") rotated 90 degrees CCW. In this case, the calendar changes at around 4:30-5:00 in early morning.

You can also use modified version of "24h-gear.stl" to tune the timing of the calendar change with 2hours step. ("24h-gear-2h-behind.stl" and "24h-gear-4h-behind.stl")