Planning on Cutting Things

I am probably making another mpcnc for just aluminum sheet, carbon fiber, and plywood. My current mpcnc is best kept just a printer due to its size and location. What I am mostly wondering is what sort of tolerances to expect? I know aluminum is probably the hardest thing to cut. I will be planning to make the machine with (absolute tube length not usable space) an x of 36" and a y of around 28". I know that Z axis is pretty much the most important thing here, so I will keep it short at about 1" of usable space, just enough to cut through thick sheets. I will be using the dewalt spindle, printing my own printed pieces, and buying the electronics kit from here.

Does stainless steel really have that much rigidity benefit? I would think that with a build of this size, the plastic pieces probably give more flex then the conduit used, then again I never looked into it. The EMT I got from Home Depot for the printer seems kind of meh. I can’t tell if the zinc coming off is helping it get more smooth or creating flat spots that make it loose. If I were to go stainless, would it be best to buy it from a local metal supply then pick it up? Shipping the stuff is just ridiculous…

I don’t think I found a video of carbon fiber yet, maybe I just didn’t look hard enough. Would you say that it’s harder to cut than aluminum? After some research, all I know is the dust is terrible for you. Maybe I can create something in the future that will put the piece being cut in a thin pool of water? To aid in cooling and preventing airborne carbon.

You’ve got a ton of questions in there.

At a small size the only benefit of stainless is the smoother surface finish but for a cnc it is not a big deal.

Tolerances, what do you need? There is a ton of information in the FAQ about that.

CF is very easy to cut, it is tough on bits so you would have to change them more often than if you used them for wood. I have videos where I cut in water on youtube.

Random question for assembly, where can I find the file to the extruder tool holder? I was trying to level my plate and I accidently hit the manual 10Z on repetier, and the poor little extruder holder was practically crushed by Z axis. Probably the hardest thing to watch cause you can just hear the slight cracking. If it ever breaks I can’t really print anything anymore, so I want to print a new one while this ones in tact for safe measure.