The limitations of CNC Milling are prototype size, axis
movement, and drill bit size.
The part or subpart being milled must be able to fit
within the machine, which is usually constricted to at most three cubic
feet.
Once the part is inside it is subject to axis movement
limitations which are usually at maximum 18 inches in each direction.
Lastly, the drill bit maximums and minimums, around .25
inches and .3 mm respectively, will
dictate the precision of parts and corners. Still, CNC Milling is far more
accurate than milling done by hand.