Just had a look on the specification for my little Dewalt D26200 - which is just really the motor unit.

It has Variable speed control from 16,000 to 27,000

So reading between the lines - fast enough for wood but not slow enough for plastic or metals.

Plastics may be something I am interested in, but generally find most polymers that I have used wrap themselves around cutters and are a pain of having to stop frequently to clean them up, especially mid cut.

But as they are a handheld router - aesthetically they do not look so good mounted on a CNC.

Those nice looking silver cylindrical ones however, look much more professional!!

WoodKnot