[Espeefan]

Lou, I'm not a real machinist, but I have been really happy with the end mills I've been getting from McMaster-Carr. I just get the high speed steel, nitride coated end mills, and so far I haven't dulled any out cutting aluminum. I'm sure they aren't the cheapest, but it's rare that I need to buy a replacement, unless I do something stupid, like run it into my vise.

In my limited experiences, I'd recommend using two flute end mills for aluminum, although I personally run four flute without issues. I don't run CNC though, and I'm sure my feed rates are much less then yours. What really makes a difference is running some kind of cutting oil, even if you simply apply it with a squeeze bottle, which is what I like to do. I save about .010" for a finishing pass, and I either take that in two passes, at .005" each, with smaller diameter end mills, or take it in one pass with the larger diameter end mills.

Your mileage my vary, and like I said, I'm not an expert. Just a guy who is basically figuring this out on his own.

What is your issue with your end mills? Are you clogging them up, or dulling them out? I've been running the same end mills since I started machining parts, which has been about 2.5 years now. My cut quality still looks great. Even on the end mills I use all of the time.