As you can see, you can build a CNC machine using cardboard and paper clips. This machine is the first of a series of CNCs that I will bring to life during the Agaday price 2016. The computing work is done by an Arduino Uno and the axes are driven by servos through 3mm threaded rods. It is simple to build, which is why this machine is suitable to teach the base principles of computerized numerical control. The machine isn't fast, nor is it precise, but that's why this cheap CNC is great to illustrate how things work and what to consider for a high quality build. First of all, you can watch the microcontroller calculating all points the pen is driven to. And secondly, each CNC has at least some backlash or the mechanics pens under load. Those weak points can be identified with your naked eye at this construction. You can get the schematics and a step-by-step instruction on the project page. The machine is made of 1.5mm cardboard, paper clips, some epoxy, wood glue as well as 3mm threaded rods and nuts. The tools needed to build the CNC are a knife, a metal bar, a caliper and a soldering iron. The electronics consists of an Arduino Uno, 3 servos and an LCD display. A 5V power supply or a 6V battery pack can be used to feed the tiny machine with electricity. When running, the CNC draws the current of up to 300 mAh, so other 2000 mAh batteries should be able to operate this machine for some hours. Instead of a router that is of news with CNC machines, this one has a fall pen, it is working as a plotter. The pen is attached flexibly to the vertical axis. Whenever the machine is powered, all axis move to the end switches. Three push buttons made of paper clips are used to operate the machine. The screen is a tiny 2x16-character LCD. You can plot capital letters or digits. After choosing a character and confirming to plot, the machine starts its job. Two paper clips are used to form a rotational sensor. 10mm of the threaded bars are covered with epoxy at one end. That insulating layer is grinded down to the blank metal at one point. When a threaded bar is turning, the paper clip switch is closed during a couple degrees of rotation. That very simple rotational sensor only works at low speeds, so that overshooting can't appear. I have demonstrated in a previous video how to build better sensors with a higher angular resolution. With the rotational sensors, the servos are turned into stepper motors, so that the Arduino can control the linear movement of the axis. One step equals 360 degrees by what we get a linear movement of 0.5mm with the 3mm threads. That very rough resolution of the simple CNC is clearly visible, another benefit of a low quality belt when talking about parameters of high quality machines. It took about 15 minutes to plot this K, it's a machine for patient operators. There is an even more simple way to use this CNC. It is still driven through 3mm threaded bars, but now they are turned by hand. The software is a set of instructions printed on a sheet of paper. A single instruction consists of the axis as well as the direction and the number of turns, and you must process all commands in sequence. Your brain becomes the microcontroller and your hands are used as stepper motors. This is a very-term and straightaway of teaching computerized numerical control. As said before, this is just the starting point of a series of 3 axis CNC machines that will be based on similar construction principles. The mechanics shown here is made of 3mm fiberboard and 4 bearings. With that construction I will test a variety of drives in a larger scale. The weak and slow servos of the cardboard machine are definitely no adequate motors for bigger machines. You can follow the evolution of CNC machines on my project page as well as on Hackaday. Have a click and give me some feedback so that I can consider your ideas for this project. Thanks for watching and I'll be back.