It is not first but also will be not last cnc router what I built. Pictures explains a lot so if you have question please write as comment.
Step 1: Gantry Parts
I have here some aluminium extrusion parts 45x90 mm
Step 2: Assemble Time.
I used here 45x90 Sigma Extrusion and 20mm Aluminium plates.
Lineer system HG20 which is enough to carry very smooth the Gantry.
Step 3: Cable Carriage and Extrusion Work Area
I used here 15x120 Extrusion for working area.
But still I put a MDF plate under the work piece to keep it safe.
If you want to cut some fine and small thing not necessary to put something under it.
Step 4: Electronic Parts
I had as step motor driver TB6560 single axis and LPT Breakout board
Step 5: Z Axis and Completion
I have here Acme Lead screw 25x05 mm and for Y axis I used 16x05 mm.
You can have data info's if you google motor type.
Step 6: Here Z Axis Done
Step 7: Finally Is Completed
I can cut aluminium very well, like mdf, pvc and all other materials.
Soon I will put more info and more detail about building.
If you need additional info please write a comment.