Thanx for the more info guys!
I'll try to find some blocks of al to see how it is working with al. For now, all (little) experience I have is with copper (with various results...
)
The tool shops in my town have pretty narrow choice of drill bits to choose from, so I'll have to search for the better shops.
So, as always, the trick is to take it easy on the handle...(pun intended)