Would a water/air powered CNC machine be feasible?

I was wondering if a water/air powered CNC machine would be feasible. Such a power method would allow the device to be powered by an outside compressor or pump or something else that supplies a flowing (pun) source of air/water.

This would allow the only parts needed to be inside the CNC machine to be made by a CNC or small electricaly driven control valves and maybe some potentiometers for position sensing.

I have noticed that most of the CNC plans that I see use stepper motors which if I understand right offer only 1 speed, but I do not really understand why.

Please tell me what you think. I have been looking at these "build your own CNC printer" and "build your own CNC mill" sites alot lately, but I have no clue yet when it comes to such things.

Bonecaya5 years ago
Short answer -- Yes,.... and No..

In times past, similar technology was used to grind grain into flour, think windmills and grain mills along rivers. Wind or water motion was transferred through a main shaft to various gears, pulleys and clutches to turn the mill stones that ground the grain. That being said, to refine that power into the small scale needed for powering a CNC Mill or a 3D Printer would probably be exponentially more difficult. Think on this for a sec,,, not only would the actual movement of the multiple axis be powered, but also the logic portion, and the heat for the extruder on the printer would have to be accounted for as well.

So... at some point this method would far surpass the costs associated with typical electrical components. Now if you used the wind / water power to turn a generator and use that to power your Mill or Printer, then YES.. it could be done!
nstenzel (author) 5 years ago
So, steve told me that I was wrong about stepper motors. Thanks for correcting me, Steve.

Is this project feasible though?
No, stepper motors work at variable speeds. True, steppers have their own problems, which is why real CNC machines use AC or DC servodrives, but there is no reason for them to be "one speed"