THE PROCESS

For this assignment, I wanted to CNC machine something personal and meaningful—so I chose my hometown: Butte, Montana. A defining feature of Butte is the Berkeley Pit, a massive open-pit copper mine turned toxic lake. It’s infamous for its acid water and the fact that someone literally has a job to shoot at the birds that land on the lake so they don’t die in it. If you don’t believe me, here’s the most famous video about it.

The first challenge was choosing a region of Butte to carve. Every spot I picked had too much vertical change for the 1.5″ pine block we were provided. My workaround was gluing two blocks of wood together to get the height I needed. I let the glue dry for 24 hours to make sure it wouldn’t gum up the CNC bit.

After gluing and clamping the blocks, I headed to the Shapeoko CNC. I used VCarve Pro to process the .stl of Butte’s topography, carefully aligning and scaling it to match the dimensions of the glued wood.

Once the file was ready, I used:

1/4” flat end mill for the roughing pass
1/8” ball nose bit for the finishing pass

This was not without hiccups—Carbide Motion gave me multiple errors, and I had to re-home the machine several times and double-check my zero. But eventually, the job ran cleanly.

After the CNC run, I cut off the side bits with the band saw, sanded down the jagged bits with 220 grit, and added a coat of Polyurethane to give it a more finished look. I repeated the sanding and staining process again for the second copy.

Then I made a concoction of resin and blue acrylic paint to pour in the TOXIC lake.

And of course I vaccumed and cleaned up my area afterwards:

WHAT I LEARNED

I learned how to use the Shapeoko. I know how to make the bit spin, how to change the bits, and how to make and process the file for the cnc.

Initially, I was really scared of the CNC machine bc in comparison to the laser cutter there’s a lot that you have to do: changing the bit, making sure the piece doesn’t mov, going across multiple computers so I can make the gcode etc. But now the process isn’t scary at all and I’m confident in being able to use it in the future.