jderou, I was envisioning that you might have a 1/4" collet also. Tell us more about the machine and material using the questions I posed above for a guide if you want more specific recomendations.
I assume your rpm will be high, probably "too" high in some regards, perhaps it is 15,000-20,000 rpm? . A cutter actually has a chip load range where it works best, assuming it is the right cutter for the job to begin with. If the chip load is too light, it tends to chatter which makes all kind of unpleasant sounds, chips carbide tool edges, and leaves a poor finish. The theoretical feed rate for that much rpm will tax even some modern CNC machining centers ability to travel that fast in certain profiles. If you have a 4 flute cutter, and figured a .0015" chip load per tooth, that is 90 inches per minute feed rate, which is moving right along, which may be beyond your machines comfort zone. So, you might look at 2 flute endmills if your rpm is indeed in that rpm range, as they will tend to run smoother, and take less power.
Also, you may have seen the high helix end mills advertised and used primarily for aluminum. We use them alot on machining centers, but you probably want to stay with a standard helix. Reason being is the high helix rate tries to pull the end mill out of the collet and at the same time pulls up on the work piece. Not the hot setup unless the collet chuck has adequate holding power and the work piece is rigid and fixtured securely.
The flood coolant is best, at least on aluminum, and if you can deal with containing the mess it will be best from the cutting condition perspective.
Also, you will probably be best off to avoid longer end mills when ever possible, and if you have a buying choice you may be wise to choose a "stub" length. Insert it into the collet as far as conditions allow, if possible up to the flutes. This will improve tool rigidity and decrease the tendancy for chatter.  |