This is a kind of post-facto blogging, although the project isn't completely done yet. I realize I should have shared it as it happened so I'm going to try to catch-me-up by going through the whole process bit by bit till it meets up with the current state.
I guess the first place to start is "what the heck is a CNC?" Literally it means "computer numerical control," which is not terribly helpful unless you already know exactly what it is anyway. Engineers are jerks like that. What it is, really, is a semi-autonomous robot that serves the very specific purpose of cutting out parts from wood, plastic, or metal. It's given a list of instructions and then goes to town on making something. Or many things. Or the same thing many times. Sounds pretty useful, right? Well it is. And by that I mean the molds to just about every product you own are probably cut on a CNC of some sort, and in the case of some higher end stuff the product itself is often cut on a CNC.
I've made a couple smaller ones in the past for cutting foam and wax, but I've always wanted to make a serious-business CNC machine that was capable of cutting aluminum and hardwoods. The first step was to determine machine size, and to do that I needed to know what sorts of components I would be using. After an extensive search I settled on a set of rails sold by an ebay dealer named "linearmotionbearings2008." Here they be:
Those are both rails and ballscrews. I'll explain the whole ballscrew thing in the next post, along with the basic design of the machine.