Unfortunately, TORMACH doesn't offer thru-the-spindle coolant.
But you should be using flood, or at least a mister for coolant to avoid chip welding.
Just experiment with a lot higher rpm and feeds.
Aluminum is a pretty forgiving material, and HSS drills are fine. No need for Carbide with Aluminum.
I would try 5000 rpm, 40 ipm, and peck at .600 (That would be just one peck to clear the chips)