A CNC router machine is probably the most useful tool a hobbyist can own, but the price for a CNC machine on the market is way more than the average hobbyist is willing to spend. You can build your own CNC with very basic tools, little knowledge of machinery, mechanics, or electronics, but be warned, these machines are inherently dangerous, so wear the proper protection and use common sense. At the very least, read the instructions and precautions on every tool you use.
Now, a CNC stands for Computer Numerical Control, but that is gibberish. It does hint you to the fact that something is controlled, and probably by a computer. It's really a mechanism that interfaces to a computer to control its movements, similar to a robot, but this machine has a specific function. It cuts or shapes things with this control. In essence, a computer precisely controls a cutting tool, like a router for instance, to cut materials such as wood, plastic or metals into shapes only bounded by your imagination.
This video tutorial will show you how to build a slide mechanism for a pipe CNC router. It is possible to build this CNC within a weekend, if you have all of the correct parts. In addition, manual cutting and power tools are at a minimum. So far, the only major tool that you'll be using is a hacksaw to cut-off some threaded rod (very simple). With the vast selection of pipe sizes, the scalability for this CNC machine is great.
This new machine is based almost solely on pipes and pipe fittings. This material really serves as the tinker toys for adults. There are a few puzzling aspects, such as the inability to create a complete square. There is a way to overcome these limitations with pipe unions. You'll see how I use these to create the z-axis.