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 demonstrate the general technique, design and how-to for the build of the linear slide bearing. The bearing will slide on an aluminum or steel angle keeping the bearing in place. First, you will need an angle, easily acquired at your local hardware store.
Cut two pieces of the aluminum angle. Depending on the method of attachment of the bearing system to the z-axis housing, the length will vary.
You will then need to drill four holes into the aluminum angle. Since a screw or bolt will need to be fastened into this hole, the hole will need to be positioned at lease half the diameter of the screw away from the inside edge. Drill four holes close to the ends of the angle to provide the most stability possible, then tap them with a tapping tool.
Finally, slide the skate bearing into the 5/16" bolt followed by screwing the 5/16" nut into the bolt to serve as a spacer. Screw the bolt-bearing-nut onto the outside of the aluminum angle.