Well, I built a CNC router, and I love it.
1. Serious "coin" is relative, but I built mine for less than a Carvewright.
2. I routinely get 1-2 thou tolerance and I made mine from mostly dimension lumber.
3. How much dust depends on what you cut. Not much from aluminum. Lots from MDF.
Get a DC system anyway if you have a router, CNC or not..
4. Only thing that is loud is the fan in the router. Get a quiet router or use a PID control system.
5. I have made lots of stuff with it, and I am still fascinated by just standing there, watching it cut.
But then, that's just me.
If you would like more info:
For a log of building it, see www.liming.org/cnc
For a log of cutting something from aluminum, see www.liming.org/ESPcopter
For a log of cutting wood items, see www.liming.org/orrey
Just my 2 cents, your mileage may vary.
I have 4X4 foot CNC router. I say, "Don't do it. It's a trap!!!" :) I ended up coughing up serious coin and time on that thing and I bought most of it premade. I ended up hating that thing for so many reasons. It's been tarped for over 5 years.
Some observations:
1. If you make it yourself, it's going to be rickety no matter what compared to a 100K rig. You might be talking about 20-30 thou accuracy which I can get with hand tools on a good day.
2. It's loud and dusty. Dusty is somewhat solvable.
3. I love woodworking. Watching a robot do it for me was interesting for about 5 minutes then got really boring.
But, that's just me...
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