If you are running without a constant coolant flow, I recommend running at 25 to 35 SFM with HSS, even with oil. When I ran a mill I ran HSS at 50 SFM with constant coolant on most steels. For dry engine machine work I run HSS dry at much slower speeds on steel and cast iron. Make sure you are feeding hard enough to make a chip which also cools the tool and reduces work hardening; a dull tool will not make a good chip.
D2 in it's soft state just is not all that hard to machine. 50 SFPM and a coolant like oil with a decent feed rate should do the job without any problems. Firm pressure with a good drill press and I don't see a problem. My guess is he is using too much speed and no oil.
