I would like to build a CNC machine myself but don't have the tools to do a competent job and would like to have one up and running rather quickly. I see Patrick over at www.buildyourcnc.com has a new 4x8 machine design that uses roller chains instead of lead screws. Is this guy crazy, or is he on to something? I can't imagine a roller chain could be at all comparable to a highly precise lead screw when moving on the X any Y axis like his machine does (his uses a lead screw for the Z). It looks like the chain will be pushing up on the stepper motor the whole time and wouldn't you think it would lose tension after time? I remember his last machine with the 4x8 option was around $2400. Now he wants almost $3000 for one that uses a bike chain?

If anyone can recommend a different "kit" CNC that has a 4x8 routable area (I may consider a 2x4 or 4x4) then please speak up.

Any input is greatly appreciated.