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 two-part video tutorial will show you how to make a stepper driver power supply for a CNC router. First you should understand a couple of concepts first. AC or alternating current is electricity that travels in two directions, backwards and forwards. Our goal is to convert normal AC electricity (usually found in the receptacle of the house) to DC (direct current). Direct current, as its name implies, is current running in only one direction at a mostly constant voltage (depending on how well the circuit is built, and with what components).
First, you need to convert the voltage to a level that is compatible with the driver board (the driver board that drives the stepper motors). The volts must be enough to power the motors sufficiently. The voltage is converted with a component called a transformer. The next component through which the electricity will travel is the bridge rectifier. Then, install a capacitor and a switch.