Mini Mill

2019-2021. When I built my first CNC router – using 3D-printed parts and bits of conduit – I found that when I tried to cut aluminum, the machine deflected, causing unacceptable chatter. In response, I decided to design and build a CNC mini mill, which would allow me to cut aluminum effectively.

A friend offered me some linear actuators that were otherwise being discarded; these were ideal for the project, but they needed a structural backbone.

A little research made clear that using aluminum for the backbone would cause horrible resonance, along the lines of what I had experienced with my 3D-printed mill. The ideal material would be cast iron, but, lacking a foundry, that was impossible. At the suggestion of a student from MITERS, I decided to try concrete.

Concrete is only strong in compression; after doing some research, I realized that to reduce the weakness of concrete in tensile stress, I would need to design pockets for threaded rods and bolts to allow for post-tensioning.

Materials: Concrete, aluminum sheets, rivets, polycarbonate, threaded rods, high-precision German router