[deft]

Hi-

I 've been interested in building a cnc wood router for a while and I just found this forum.

I have a number of design questions, I've read most of the posts here and it looks like you all might be able to help me out...

machine I'd like to build would have a 24" x 36" work envelope, and be used primarily for routing plywood, mdf, plastic, possibly aluminum but that isn't so important. I'm thinking of using a laminate trim router, or a pc 690 I have laying around. Ulitimately I would want to get something with varible speed but that isn't necessary right away.

I'm pretty confident on the mechanical parts, but the electrical parts frankly confuse me.

i understand the basics in that I need a driver for the motors but I don't know what driver - motor combo would be appropriate for the size of machine I'd like to make. In another post someone suggested 250-300 oz/in for a 5' x 9' machine. Is there a rule of thumb? Like 40 oz/in per 1/8" of material (I'm assuming plywood). Thus 240 oz/in for 3/4", 80 oz/in for 1/4"? Or is the mass of the machine (say gantry or moving table) more critical than the material cut?

The other part I'm unsure of is selecting a driver motor pair that will work together.

I'm thinking of building a cheap cnc router first (ie with stuff I have laying around) but i'd like to eventually migrate the motors and drivers to a better machine when I can afford it.

thanks in advance