Couple of points:
If you used an HSS 2 flute endmill on mild steel, then you would generally start at around
5k RPM. You would want to run coolant, or you will fry the endmill. You could use solid carbide, but then you would be low on the speed side. As far as feeds are concerned a 2 Flute HSS endmill could take a chipload of .001 inches/rpm/tooth, which translates to 5000 X .002 = 10 inches/min.
Consider the lack of cooland, and the rigidity of your machine, and the clamping of the workpiece. The cutting forces are considerable.
People do it, but I would tread lightly....be safe!