My first CNC machine... thoughts?

[telmnstr]

Hello all,

I've been intruged by CNC machines ever since I saw an advertisement for a kit in the back of popular mechanics 10+ years ago. I looked around to see if anything was offered similiar to it, but couldn't find such a thing... basically it looked like two linear auctuators about 4' long in parallel serving as X axis, Y axis was yet another one, with the router attached to it.

So I've decided to build one from scratch. The goal here is cheap, as I'm budget limited. Perhaps if it works well in the future I will expand, or maybe get lucky and find a steal on a commercial unit via auction circuits.

My thoughts are this:

2x4 frame of about 5.5' x 3.5', 2x4's on their side
Gas pipe for X axis (gantry style), similiar to pipe dream
Roller shake bearings for X axis
Threaded rod from hardware store for linear auctuators
powermax II or similar steppers from eBay coupled to threaded rod
homemade controller card (driven by lpt port)
EMC for Linux for control
Some sort of slide for Y and Z.
Dremel (is there something inbetween a dremel and a full sized router
that would be better?)

My initial goals are to mill out small grooves in wood or plastic for a CD changer project, which uses the same types of motor drives as the mill (looking to make a homebrew 10,000+ disc CD changer, and need accurate cuts for the grooves to hold the discs).

2nd use will be for milling out thin metal and plastic project box covers
(for rs232, ethernet, power, fans and the like). Metal might be too rough
for my planned mill? I'm NOT looking for speed.

That was all fine and good, until I found this:
http://www.imagetogcode.com/
Now I'm kind of wondering if my simple design idea would suffice for running
off projects like those?

I don't expect super great accuracy on the first one, the more I keep costs down the better. I have plenty of PC's and have worked with stepper motors before (floppy drive style) so this doesn't seem terribly difficult OUTSIDE of all the alignment issues and of course the precise measurements and such that are needed.

Any thoughts? Any idea for simple improvements? I've looked around at a good number of web sites and there is definitly quite a bit of information out there. Most people are constructing much smaller setups, so I suspect mine might not be the flattest thing ever... but as long as it can aid in my projects, I'd be a happy person.

Plus milling out pictures of Albert Einstein in glass or lexan would be entertaining :-)

Oh, quick question. A while ago my mother was given a gift of a piece of marble that had images cut into it. The "pixels" were black, however. Is this type of thing achievable with a CNC mill? Or is this done with a laser setup? Anyone seen it done? Do they mill out the "pixels" then go back over it injecting the "black"??? It is an impressive piece of art that was most likely done computer aided... I've seen some REALLY neat stuff looking around at laser based systems (lasers are a hobby of mine, but all my equipment is visible argon, and not really good for that kind of work).

Any information appreciated in advance! I have a habit of keeping good notes and pictures on all of my projects, this will be no different... so I will be sure to post the information here and on my homepage at http://users.757.org/~ethan