I need to drill 7/16" diameter x 2" deep holes in 6061-T6 aluminum. Making 50+ parts, 9 holes each. Problem is my cnc router doesn't have low-rpm torque. How do people with high-speed spindles mill or drill deep holes?

From what I understand, and recently tested, just pushing up the RPMs into a range my spindle can support isn't a good answer. At least using standard high-speed-steel twist trill bits was pretty ugly, resulting in pilling/etc even when I got it to work by shallow pecking. I understand my chipload was way too small at that high-rpm/low-feed setup but watching it bog, my guess is horsepower requirements at higher feeds won't work.

Is the answer to use a carbide (full or carbide tip) twist drill bit, just use high speed (peak torque is above 15K RPM) and see what feed it can sustain?

Is pre-drilling a pilot hole part of the solution? I hate to do more (manual) tool changes but if that's the best solution, ok.

Or should I use a smaller end-mill, spiral cut the hole & try to evacuate the chips the best I can? Would high pressure compressed air (mist) or medium pressure flood remove chips from this deep pocket better?

Right now I'm thinking a combination of using carbide-tip twist drills, pre-drilling a 1/4" pilot hole + shallow pecking might have the best combination of job time/tool cost/etc and might be the best way to go.

Or am I missing something? I'm pretty new to the cnc-machining game so if some folks with actual experience could tell me what works best I'd really appreciate it.

Thanks