I have a bunch of these linear actuator systems for my work. I also have my own hobby CNC that I upgraded several times when I started with a cheap amazon one to workbee to workbee with linear rails. I am here to tell you that if you want to CNC any aluminum, using 3 or 4 of these is going to be a bad idea and you will need to be realistic. Many CNCs under $1k can do aluminum, just very very slowly. The cheaper CNCs and anything made with just V-wheel linear actuators lack serious rigidity so even if you had two of these for a dual Y, a single X or Z gantry will have a ton of flex. If you want to see the minimum form to do aluminum with something similar checkout the workbee or sainsmart proverxl which are pretty much the same. There are probably some hobby CNCs on amazon from like Sainsmart or Foxalien that can do aluminum but that is at really slow speeds and feeds (trust me I had one and I then had the ProverXL). We're talking to cut out a circle at 1/4" aluminum you'd probably do that in 15 minutes. This same question gets asked all the time and for a 3D printer, sure you can use these. A CNC needs rigidity and I think there are some linear rails 3020s (something like this ) which probably will give a decent performance for aluminum for under $1k. So in summary if you want to do larger work area and enough rigidity for aluminum, I think a ProverXL or workbee is a very miminum. Above that should be anything with linear rails like a queenbee, shapeoko, etc.