You know that old saying about, you're only as good as the sum of all of your parts ... well no where is that more true than when you want to build or buy a CNC router. If you buy the biggest spindle motor you can afford and put that on a 5 pound gantry with a 3watt stepper motor, you're going to have some issues, I guarantee. Of course the opposite of that is true as well that if your spindle motor is undersized but man, can it get around the table in lightening speed, breaking bits will be a daily occurrence as you push the power limits of your cutting tool.

So the parts for a CNC machine must match your needs, but also match each other or the weak link in your CNC router design will be a maintenance headache at the very least or a serious limiting factor in your ability to optimize the capabilities of the rest of your machine.

In order to sort all that out, it first helps if you know what parts make up a CNC wood router and what are the key points of difference between all of the options you might be presented with. Here we'll talk about all the various parts of a CNC machine and the options you should discuss with your tool supplier. Remember they're certainly NOT going to tell you where compromises have been made in their machinery design, if they figure you don't know the difference.. of course maybe they don't know the difference either.

I learnt this one the hard way after a significant amount of dollars were invested in a machine that had no true engineering input ... they didn't even lock down the position of the Z axis ball screw... but that's a story for another day, my stupidity that I didn't do enough homework, and didn't know better, so here's what I have learnt NOW ... Karen

CNC Spindle:

This is the workhorse of the machine. It's what cuts, drills and carves. I've seen machines rigged up with industrial CNC spindles, various versions of off-the-shelf woodworking routers and right down to very small laminate trimmers, rotary tools like a Dremel™ and even one with a die grinder (don't think that worked too well)

Motion Control Systems:

This is a very broad category and typically the most complex. It includes all the controls and motors that make the CNC spindle go where you want it to go, and do that repeatedly. That includes the stepper or servo motors to power the movement, rails (THK,ball & screw, rack and pinion etc) that guide the machine and all the control electronics (controllers, encoders, breakout boards) that interface between your computer and the actual movement of the machine.

Work Table:

The easiest question usually is defining the space available .. note that I'd didn't suggest GETTING the space (from competing uses??) is the easiest, just measuring it. So knowing what size possibilities you have to work with is the first question and then a discussion on all of the design configurations that are available flow from that.