RepRap parts cast from epoxy resin?

I have no access to a rapid prototyper, and no experience in machinine precession parts. I have a little experience as a model builder, and have cast parts from expoxy resin using molds that I've made. This usually produces a good looking result, but probably doesn't produce parts within the kind of tolarances an engineer might want.

So, my question is, how precisely made must the plastic parts for the extruder head be? It looks like something that I could build from wood and epoxy putty and then cast from alumilite, if the tolarances don't have to be super precise. And the way the parts fit together, it looks like there could be a little leeway there.

Has anyone built one of these things using something less precise that rapid prototyped parts?

I have made a Darwin-clone out of plywood (19 and 9 mm), 44x44mm hardwood, stock aluminum square and rectangular tubing and MDF. This actually seems to work, although I can't tell yet if the accuracy is sufficient. In general, tolerances are +/- 2.5 mm for most parts, and most can also be made using fairly common power tools. Most important one I used was a decent drill press.

Joost

+/- 2.5 mm is a pretty loose tolerance. I think that I could achieve that.

Ooopp... made a mistake here. Should have been +/- 0.25, not 2.5 ..

Joost

A quarter milimeter? Still might be able to do it.