Why would you build a CNC?

My last major project was building a boat. It was much the same as building a CNC router. You don't build a boat to save money. You can buy one much more cheaply than building one. The only rationale for building a boat is that you want to build a boat.

As I do my planning for my CNC router, I think about my rationale is for building a CNC router. For me, it is for fun and for a platform for my real goal of working on the coding end of it. Actually, for not that much more money and a lot less effort, I could have just bought one of the Chinese pre-built machines or one of the kits. Something like Zen Toolworks or Buildyourcnc.com would be a lot less hassle. They are not really charging that much for them when you consider the extra shipping for ordering from multiple vendors and the time spent on sourcing materials, let alone the design time. If I factored my design time at my normal pay rate, I would be much further ahead just buying a pre-built machine.

If I were using a CNC router commercially, or even depended on it slightly, I would seriously lean toward one of the commercial products. At the very least, I would use standard drivers, motion components, and motors. You really can't afford to have to tinker with stuff if you are doing it as a business. Readily available replacement parts beat cheap replacement parts any time. Just having a machine sit there and not be working is a losing proposition. It makes jobs late. It loses you customers.

My initial designs for my CNC router will probably be a failure. It likely will take several versions until I get something that I am happy with. I am building contrary to what have been proven successful designs. I am purposely building an low powered machine. For a few more dollars, I could have bought more powerful steppers. I want to see how well I can move things around without brute force. The other thing that I am focusing on is building a rigid machine that is light enough to be portable and inherently stable enough to move around and not have to re-level or recalibrate. If I can get these two things pinned down, I will be happy.