A question about turning aluminium

[pugs]

Thinking you probably got brazed carbide tools which are just flat topped. They suck for alum, grind up some hss blanks with a nice little nose radius and high rake angle, extra sharp and polished a bit if you can.

SFM of around 200 is good for alum and hss bits. so a 1" dia would be 800 rpm. can go faster but that should be a good starting point. if you save up and buy some carbide insert tooling someday with alum specific inserts can push well over 1k sfm.