Mechanical Sunrise Sunset Clock - shows 24-hour time plus sunrise and sunset indicators that change throughout the year based on astronomical calculations. 

Sunrise / Sunset Cam profiles designed to be tailored to a specific Latitude/Longitude location. 

---STILL IN DEVELOPMENT---

This upload includes all 3D printable parts. You'll also need some brass tubes, rods, and a quartz clock mechanism. Working on making this easier to assemble, including fixing some tolerances, detailed parts list, assembly guide, Cam profile calculator coming soon!

You will need heavy wire cutters to trim the stainless steel rods to size, and a way of cutting the brass rods (I used handheld coping saw).

A note on rotating parts (gears):

Rotating parts are deliberately modelled with centre hole too tight - the steel rod will not pass through straight away. This is because if they were printed with holes that fit the rods the chances are that they would be too loose and wobble around the axis. Axial alignment of rotating parts is very critical for the clockwork. The best way to achieve perfect alignment is to print deliberately too tight and gradually erode the centre hole, first with 1.5mm drill bit and then second with a burred piece of the steel rod. Eventually the gear will fit perfectly on the steel rods, you will know when it's right because it will spin on the rod with very little resistance and no axial wobble. 
 

Questions? Please ask!

Some more detailed notes about the project:

• Varying rotational profile of each Cam results in rotational movement of the corresponding sector arm ‘follower’, which is then magnified by the ratio of the sector arc to the small centre gear to get the desired annual sweep of the sunrise / sunset indicators.
• The uploaded Cam profiles will produce a sweeping arc of sunrise / sunset for midlands UK, with annual sunrise variation between ~4:40 to ~8:20, sunset ~15:40 to ~21:30.
• Variation for other UK locations will be minimal. 
• Larger Lat/Long variation from the Greenwich Mean Time will require tailoring the shape of the Cams
• Accuracy of the annual rotation will be 12 hours slow per year - Annual rotation achieved by reducing 12hr clock mechanism by 3:1 six times (resulting in rotation of 8,748 hrs).
• Accuracy of the Hour hand determined by the Quartz mechanism - Hour hand indicator driven independently from the annual chain, through a separate 2:1 reduction to achieve the 24-hour rotation.
• No adjustment for daylight savings (British Summer Time) - my strategy is to leave the clock alone and accept that a hand pointing straight up on the clock face during UK summer indicates 13:00 instead of midday. This reflects the astronomical reality of 13:00 being the middle of the day in British Summer Time.
• Accuracy of the Sunrise / Sunset indicator hands probably to about +-10 minutes. Iterative development could improve accuracy (e.g reduce backlash). The real perception of the sunrise / sunset event happens over a period of time similar to the accuracy - so i decide to accept the +-10 and treat the clock to be a ‘time of the day feeling indicator’. i.e “We are about three quarters through today's daylight hours” instead of “it's 23 minutes until the sun sets”. 

Change history:

• Update 30/03/2026 

  V2 files - update to some tolerances and minor improvements. See attached V2_changes.txt