Variable speed controller for 240v brushed motor power tool

[DXX]

I’m looking for a simple way to reduce the motor speed on a brushed motor router tool so I can machine thermoplastic without it melting.
Effectively I want to use a wood router as a milling machine.
I would also use compressed air to cool the cutter
27000 RPM no load, 500W rating, 240v single phase.
Can anybody recommend an off the shelf controller?

 

[Loz]

A Variac perhaps?

 

[DXX]

A Variac perhaps?
View attachment 138176

Thanks, I hadn’t heard of these before.

 

[Dilbert]

I personally would be looking at a variable frequency drive {VFD}. It will be cheaper than a good variac and will also provide much more torque at lower speeds.

The speed is electronically controlled by adjusting the frequency of the AC supply.

You need to find a 1 phase to 1 phase VFD which are less common than the 1phase to 3 phase devices commonly advertised.