[Levansic]

The proposed plunge speed is what caught my eye. A good rule of thumb is 1/10th the fully engaged (100% cutter width cutting) feed, and avoid straight plunges like the plague.

If you plan to do NC cutting, as opposed to hand cranking, you really should step up to carbide cutters. They can cut 2-4 times faster and last 10 times longer in total cut. Additionally, you can get some great ZrN coated mills, with edge geometries suited to cutting aluminum (proper rake and adequate clearance), and cut up to 10 times faster, without suffering the dreaded aluminum buildup on the cut edge. Aluminum buildup leads to galling, essentially friction welding. This breaks endmills.

I will second the 3-flute cutter as a great go-to for aluminum. It is more rigid and allows 50% more feed than a 2-flute, and has better clearance than a 4-flute. Chip evacuation is critical for aluminum.

-- Len