Hello all! I'm relatively new to the world of CNC machining and I intend on building my own machine for personal use. In terms of experience I've done some CNC work with wood, and have significant experience with laser cutting. Other than that I've done quite a bit of woodworking and metal work as well.
As I've read about building a CNC, the more I realize I don't know all that much about the workings of the machines. There are a lot of forum and sub-forums so finding specific guides has been rather difficult, mostly because I don't know what I'm looking for. If anyone knew any explanatory or step-by-step guilds to building a CNC machine that would be hugely helpful!
In terms of building my very own CNC machine I'm looking for a three-axis machine with a 2' x 4' bed to be used almost exclusively for woodworking with the occasional piece of aluminum. I'm not opposed to building from a kit but from past experience usually you get more value by purchasing the parts yourself. My budget is $2000 but I could extend that if necessary.
Any advice?
Thank you!
That is quite a large machine so you may want to avoid the cheaper controllers and go for something with NEMA 24 or 34 motors.
Also bear in mind that many home brew machines cannot operate to the speeds and feeds of an industrial machine.
Frame rigidity is the key factor in a home build.
Get that right and you are off to a good start.
With a machine that size you may also want to invest in at least 16mm but preferably >20mm ballscrews.
There are lots of control kits on ebay etc which will give you most of the electronics.
You will be on quite a tight budget at $2,000 but it is certainly do-able
Once you get above 600x900 the prices tend to jump over the $2,000 mark
If you can build your frame yourself you may save a lot there.
There are also a few "off the shelf" complete kits around that size primarily aimed at wood.
Most machines are specified in mm apart from a few expensive US versions
Also do not cheap out on the spindle as that is another major factor in reliability.
A little larger that your requirement but a very good price
Also use the search terms "ox" or "work bee" for cnc woodworking to aid your search.
I use the kits here BTW but smaller than your size and so far have found them exceptionally versatile although I do throw a lot of my own touches into them being a millwright / engineer.
Started of with homebrew and I do mean home brew from whatever was laying around.
Apart from many other posts in this section there are some useful tidbits in this post even though we wander on occasion 
I would recommend watching some youtube tutorials of other people that built similar CNCs, see if you can learn something; for example what problems might arise and how do they solve it (for ex backlashing)
Backlash is much less of a problem with real ballscrews over the acme type approach.
Even with the screw type it is quite easy to overcome with the various anti backlash nuts available.
It is simply two opposing nuts with a form of adjustment or spring.
Bigger issues come from beds being out of alignment to the gantry and the z axis being out of alignment to both the bed and gantry.