I've currently moved over to blogging at http://mathcraft.wonderhowto.com/

Here I will be posting about 4 times per week and will have a project every week with more in depth information and a how to component and templates. There will also be a user forum for people to submit pictures and ideas.

Thanks! I hope to see you there!

Copernican Planetary Orrery (Gears for Venus)

Tonight, I spent a little bit of time on the wooden orrery (See post below for description) and finished up the gears for Venus. These are the last speed multiplying gears (the final gear spinning faster than the driving gear). There are 39 teeth on the drive gear and 24 teeth on the gear connected to Venus. Since Earth's gears will be one to one, this gives a ratio of 24/39 compared to an Earth year. Multiplying by 365.2425, this gives Venus a orbital period of 224.76 days. In actuality it is 224.70 days. This gives an error of 1 part in 3700...even better than the gears for Mercury.

The gears for Venus out of 1/2 inch ply

Stacked on top of the Mercury gears using coins as spacers. They are raised only slightly more than they will be when finished.

Side view of gear stack.


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