Working on a design to work primarily in steel and aluminum
Heres the question


Cutting Speed tIMES 4 oVER Bit Diameter = RPM
Mild Steel Cutting Speed = 100
Brass = 120
Alum = 300


So I was looking at a woodworking router with a speed of 25000rpm.
It can take a half inch shank. So rpm of a half inch HSS end mill is 800rpm.
Thats vastly different then what the router wants to do.

So is there a way to use gears or belts to lower the speed down to the proper range or using a electronic device to do this?
Or another spindle option that I don't know about?
Jon