Enrico's Oracle

I built this as a Secret Santa gift for a friend from our Curse of Strahd campaign. The project began as an excuse to finally learn Fusion properly, but it gradually became both a mechanical experiment and a portrait of his character's journey through the campaign.

The mechanism grew out of sketches exploring ways to roll an entire set of dice mechanically. I started with a 120-tooth external ring gear. Since 120 is the least common multiple of the standard die sizes, it made a natural foundation for the system. The idea was partly inspired by Not an Engineer's Toolroom Takeover project. From there, I modeled a separate gear on a spoke for each die, then shaped the carrier around them with Fusion's curve tools.

The limits of my tooling helped determine the final scale. My smallest end mill was 1 mm, which established the minimum practical tooth size and, in turn, the overall diameter of the piece. I machined the individual gears first, followed by the carrier and finally the 120-tooth ring. Once those parts meshed reliably, I knew the core mechanism worked and could begin developing the housing and decorative elements around it.

The visual design represents the three forms my friend's character has taken so far during the campaign. The reliefs on the top are derived from the character tokens used for those incarnations. I prepared the artwork in Illustrator, converted the two-dimensional images into relief models with MakerLab's image-to-3D tool, and incorporated the resulting forms into the machined brass surface.

The marquetry on the bottom continues the same idea. Its text is a small puzzle for the recipient, describing the transitions between the character's different forms. Before cutting the final bottom plate, I used the Carvera Air's laser module for the first time and ran several experiments to see whether the veneer inlay would work. The central section came out well, although the side pockets were slightly too shallow and suffered some tear-out during finishing.

Nearly every component was made on the Carvera Air. Most of the structure was cut from 4 mm aluminum sheet, while the top and bottom rings were made from 4 mm brass. The wood veneer was cut with the machine's laser module. M3 brass bolts hold the outer assembly together, and the main screw is an M5 grub screw fitted with a custom cap.

Each of the smaller gears runs on its own miniature bearing, while a larger bearing supports the interface between the housing and the gear carrier. Some less visible details only emerged during testing. Tightening the main screw directly against the assembly could seize the large bearing, so I added an internal bearing lock ring. I also added small indents and detents around the housing screws to remove the play caused by their tolerances.

The engraved artwork required its own workflow. I exported the part sketches from Fusion, developed the vector paths in Illustrator, and then imported them back into Fusion as sketches. Trying to model all of that detail directly was more than Fusion wanted to handle, but the imported paths worked well as the source for trace engraving operations.

Most of the machining was done with 6 mm, 3.175 mm, 1.5 mm, and 1 mm flat end mills, along with 0.1 mm and 0.2 mm engraving cutters and a 3.175 mm ball end mill. I also used M3 and M5 thread mills, a chamfering bit, and the XYZ touch probe. Almost every component required a second operation, so reliable alignment was essential.

The finished object wasn't the result of a fully resolved design drawn up in advance. It evolved through machining tests, failed assumptions, and small mechanical discoveries. I began with a simple gear concept, adapted it to what my tools could actually produce, and added the artistic elements as my confidence grew. That learning process ended up being one of my favorite parts of the project. Making it for a friend gave me the perfect reason to see it through.