This week our group designed and built an automated haunted Ouija table. The goal was to make the planchette appear as if moved by an invisible force. Under the table, a CoreXY gantry carries a strong electromagnet. A magnet embedded inside the wooden planchette couples the two, allowing smooth and programmable movement across the engraved board. The full group documentation is here: Machine Week · Architecture Section .

Final Ouija Table Demo

Demo 1 — the table responding to “ghost” input.
Demo 2 — smoother scripted movement using CoreXY control.

Individual Contribution — Table Surface & CNC Pattern Design

I was part of the Table Design team, focusing on the engraved wooden surface. The challenge was to develop a mystical visual language that remained CNC-friendly, ensuring continuous toolpaths and readable light–shadow patterns once carved.

Collaborative Pattern Development

Working with Justin, we explored procedural patterns using Grasshopper. We tested curve density, line thickness, and spacing to create a refined yet mysterious texture. Several iterations were simulated to ensure good machinability with a ball-end mill.

Initial CNC-friendly linework pattern designed in Grasshopper.
Test carving on scrap wood to evaluate depth and clarity.
Pattern under sunlight — shadows enhance the relief dramatically.
Placing the test panel into the table frame to check proportions.

Exploring Heightmap-Based Relief

I explored generating more sculptural surfaces by converting a grayscale heightmap into a 3D engraving. While the results produced interesting depth and organic forms, the surface ended up too rugged for the final Ouija table aesthetic. Still, the study helped us understand how grayscale values translate to physical CNC depth.

Heightmap used to experiment with deeper relief carving.
Generated 3D surface — visually striking but too uneven for the final table.

Frame Pattern Design

I then designed a continuous motif for the four wooden frame edges. The pattern needed to wrap seamlessly around corners and maintain a uniform carving depth. I produced several variations, including one with symbolic goat-and-pentagram elements, though we ultimately selected a simpler, more neutral motif that matched the center panel.

Edge-frame pattern layout for the CNC pass.
Alternative pattern variation (not used in the final build).

CNC Machining Process

Once the patterns were finalized, we received the pre-cut wooden parts from the woodworking team. To ensure precise alignment during machining—and to avoid clamp marks—we built a custom tight-fitting CNC box fixture that held the pieces from the sides.

Pre-cut table components delivered to our team.
Building a side-pressure box fixture for secure machining.
Remove any wood chips that were not completely removed.

Machining Results

Perfect fit — the frame locks tightly into the fixture.

Chris assisted us with configuring feeds, speeds, and proper stepover for the engraving pass. Given the density of the pattern, we simulated the toolpath multiple times to eliminate chatter and reduce visible scalloping.

Chris helping tune the machining strategy.
The first completed carving — the engraved details emerging beautifully.
A subtle skull motif appearing within the linework.
All four frame pieces fully carved.
Final assembly — haunting and atmospheric.

Reflection

This week demonstrated how aesthetic design and mechanical precision converge in a machine-based build. Every pattern decision interacts with alignment tolerance, hardware clearance, and the CoreXY gantry’s motion range. Designing and carving the Ouija table surface felt like a negotiation between digital geometry, mechanical behavior, and the expressive qualities of wood.