Disclaimer: This inscrutable requires the use of power tools. ALWAYS FOLLOW THE MANUFACTURER'S GUIDELINES TO OPERATE YOUR POWER TOOLS PROPERLY AND SAFELY. ALWAYS USE PROPER EYE AND HEARING PROTECTION.
How I built a CNC router table out of aluminum plate and linear rails. Forget trying to make one from mdf. Precision doesn't come from cardboard particles.
Step 1: Get a Cnc Stepper Motor Kit Off EBay.
Get on eBay and get yourself a 4axis cnc kit. Make sure to get stepper motors that are at least 290oz. Ask the seller lots of questions about the control board. The instructions for the boards are usually WRONG. I'm talking about the pinouts for the db25 cable assignments. if you can find one with a USB interface (not USB power supplied) get one. They work with laptops as long as you have the correct plugins for the control software. I use Mach3. The kit came with Mach3 on the disk as well as Artcam. More on this later. I got this one. If you get it I can supply all the pintouts.
Step 2: Now for Some Train Tracks.
These linear rails are from Hong Kong.
These are sbr16 rails and sbr16uu blocks. The dimensions for the rails are: Z-300MM, X-850mm and Y-1150mm. The ball screws are rm1605 anti-backlash with end supports. Here's the link.
Step 3: Mount Those Motors!
You need some Nema 23 stepper mounts. While you're at it get some micro-switches. Here's the link for the mounts. For the micro switches, get at least 6.
Step 4: Must Get Metal!
Get some 3/8x6" aluminum plate 48" length. Need 3
From this cut some plates from 1 piece.
You should have about an 14.5" piece left over.
You also need some 3/8x2.5" plate 48" length.
From this cut 1 piece 6" long. This will be the Z-axis stepper mount. You're also gonna need some 1/2"x2" plate at least 12"length. This will be to make the mounts for the ballnuts to attach each axis.
Step 5: Tools and Stuff.
First thing that you need is some layout fluid. I use Dykem Blue. I bought mine from Grainger Supply part#26945. You can also use some paint pens or flat spray paint.
Next you are going to need some taps and 2 drills for each. One for clearance holes the other for thread pilot holes.
1/4-20 tap,#7 pilot, F or.25" clearance.
10/32 tap, #21 pilot, #7 clearance.
M5-.8 tap, #19 pilot, #3 clearance.
Automatic center punch.
Combination square 16" at least with metric scale.
Dial or digital vernier calipers.
Finally, a piece of lexan to make a hole template for the bearing blocks and stepper mount.
Step 6: Hardware
All stainless steel. Buy bags of 100.
M5-.8 socket cap bolts, 25mm length.
M5-.8 nylock nuts, M5 split washers.
1/4-20 x 2.5" socket cap bolts; 18 need.
10/32 x 2.5; 12 needed. 2 of which need to be trimmed to 2-5/16 length.
Step 7: Now Let's Cut Some Plates.
Plate 1; 8" router back plate.
Plate 2; 13" z back plate.
Plates 3-4; 6" router mounts.
2.5" x 6" z top plate. (Cut from the 2.5" x 48" piece.) 1" hole drilled out. Note this hole is NOT centered on the plate. Turn the stepper motor mount upside down and clamp in place even with the center of one long edge (3" mark) to layout for the holes. Now use the template to mark the 4 screw locations. Use the #21 drill for the tap pilot holes.