As far as most newer manufacture power tools (my Jet 18" Band Saw, as an example)....
The wires in the cord are both switched (black and white), and when converted to 240 volt, both 240 volt wires being black, white, are therefore switched.
It merely requires that the motor wiring be changed for the higher voltage, and that the cord cap (plug) be changed for a dedicated 240 volt circuit.
The NEC does not apply to Machine Tool Wiring. Just buildings and structure.
Makes it really simple when converting from 120 to 240 volt wiring.
Change the motor following the nameplate, change the plug, feed it 240 and smile a big old smile!
Technically you are required to mark the white wire with tape to show it as a current carrying conductor. (Black, blue, red, etc.)