The motor fitted to these are most likely Universal motors, if so the speed controls are most often simple Triac controlled type.
It may be feasible to use a 120vac model router off 240 with a Triac controller that has been tailored to limit the output power.
You will need some kind of speed controller anyway.
You would need to ensure the mean off load voltage did not exceed 120 as you will over speed the router.
Al.
CNC, Mechatronics Integration and Custom Machine Design
“Logic will get you from A to B. Imagination will take you everywhere.”
Albert E.