Scrap Parts CNC
This project started as a personal challenge: could I build a working, mini CNC machine using only parts I had on hand (scavenged and spares) and 3D printing. I was mostly successful: I did make a functional CNC machine over two weekends but I had to break the rule and purchase about $20 worth of new parts.
The machine is perfectly capable of cutting wood, plastic, and circuit boards. It can engrave aluminum but struggles to cut it.