A question about turning aluminium

[carp]

So yesterday i got finally got a lathe and today i had my first go on it, i was making some rollers for my excavater tracks, anyway it took me about 3 hours to turn out 1 roller which seemed a bit slow to me, anyone got any tricks to make it a bit faster? was running at 125spindle rpm mainly because it was all new and didnt wanted to smash anything in the machine.

cheers