General question; milling slots

[f350ca]

Also, when cutting a slot a 3 or 2 flute cutter is better than a 4. With a 4 flute cutter, the edge at the front of the cut is flexing the tool toward you if your cutting to the left, this causes the cutting edge closest to you to cut deeper while the edge away from you is pulled from the surface.
The speed sounds right for steel but should be twice for aluminum. Bronze Im not sure.