Perpetual Calendar Clock

##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")