SP14 and SP15: Moon Phase Clocks

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SP14 is a large weight driven wall clock with a prominent moon phase dial. SP15 is a similar design in a medium size format suitable for printing on a "mini" sized printer. Both have an 8-day runtime and an accuracy of 1-2 minutes per week. The moon phase dial stays accurate within 1 day every 2.6 years.

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Both clocks follow the same easy to build design style as my other new clocks. The bill of materials has been reduced and the only machining required is cutting the arbors to length. The pendulum components drop into place without glue. The winding key is easier to build and more stable. Multiple size weight shells are provided to allow filling with either lead shot or BBs. 

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SP14 is 9" wide by 22" tall and 6.5" deep (225mm x 560mm x 165mm). The minimum printer size is 210mm by 210mm. Total print time on a Prusa MK4 is around 90 hours using 1.7kg of PLA filament.

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SP15 is 7" wide by 17" tall and 6.5" deep (175mm x 430mm x 165mm). The minimum printer size is 170mm by 170mm. Total print time on a Prusa MK4 is around 70 hours using 1.3kg of PLA filament.​​

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SP14 was originally released in February 2024 using involute style "fancy gears". It ran reasonably well, but I started developing some improved cycloidal style "perfect print gears" soon afterwards. SP15 and an update to SP14 using the new gears was released in April 2025.