Being a noob to machining and metal working in general, I'd like to ask what a good general purpose cutting oil would be. I was given a gallon of oil in an unmarked bottle when I bought my Atlas lathe(I think the p.o. "liberated" it from bulk from his work). It was a little dark and smelled like the oil I've used to thread pipe. There are a lot of choices out there- tapping, cutting, grinding, water soluble, lite, dark, has sulpher& chlorine, doesn't have it, rancidity safe...... And then theres those who say to use bacon grease, lard, kerosene and wax or other home brews.
I want to keep it simple, I use mostly mild steel, aluminum and brass for my projects so I'd like to get something that works for all, doesn't stain and cleans off easy, works right out of the can. Is there such a beast? I've heard that the Mobil products are good, anybody here use them?