Milling Planetary Position Jewelry

For Valentine’s Day 2020, I made my wife a necklace with three CNC-milled charms, each with a representation of the positions of the planets on specific important days: the day we started dating, and the birthdays of our two children.

Generating Artwork

First, I developed some Python code to generate the images I needed. Since it was graphical and I knew I’d have to play around, I created a Jupyter notebook. (You can play around with my code, too! Change the date and make your own with Binder or Colab!)

You can click through on the Python, but I use sunpy to get coordinates of the planets at a specific time.

After I played around with the data, I created a ray for each planet, starting from the sun, aimed at the planet.

I then saved an SVG for each of the dates for import into my CAD/CAM tool.

CAD/CAM; or “transforming the artwork to something millable”

Once I had the SVG, I created a Fusion 360 project. I made a sketch with three circles, imported the SVGS, and added little holes for the jump rings. An extrusion later, and tada!

The charms in Fusion 360

In the Fusion 360 CAM view, I set up a trace operation with an engraving bit, and then a 2D Pocket and 2D Contour operation with a 1/16″ flat end mill.


I loaded up an anodized aluminum wallet card (which also lasers really really well, by the way!) into my Othermill V2, and a few minutes later, the charms were ready.

The mill right before it engraved the line art into the anodized aluminum card.
I took a video of the mill cutting the charms out.

After loading the first set onto jump rings and then onto a necklace chain, the charms seemed too big, so I went back to Fusion 360 and shrunk the charms down, recut, and a few minutes later, I was finished.

The larger charms, before having their edges buffed.


I think this project turned out quite well. Using a Jupyter Notebook was a huge win, although PyCharm in late 2019 tends to freeze when using it. I really like that using Colab or Binder, folks can open a webpage and use my code–without me having to think about it being a web service when rigging code together. I love laser cutters and 3D printers, but sometimes milling is such a perfect fit for a project.

(This project (1, 2) is also on Instagram.)

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