I just got my hands on a sherline 4400 mini-lathe. I know how metal
behaves with a file/saw/hammer- just not with machine tools.

I've been playing with some brass and learned about the drill bit leaving
triangular holes and other non-obvious things. I was able to turn down
some aluminum castings I made, but other than just making random shapes,
I'm somewhat at a loss as to where to get started. There's got to be
defacto books written 1000 years ago I need to grab.

What's suggested around here?