The finish on the 3 flute should actually be a bit better, unless you're using a wiper insert in the 5 flute. The trick is to calculate the feed instead of guessing.
The major consideration for power in a facemill is how many teeth it has, not the width. You should be able to run a 5" wide three flute facemill in aluminum on most machines successfully, it just won't be the fastest thing ever.
For large widths in one pass on a low power machine, or for excellent surface finish, the best suggestion is to use a flycutter and crank the depth in to reach the machine's capacity. |