Machining is a subtractive manufacturing process where the material and cutter are moved precisely relative to each other, either manually or via computer numerical control (CNC). As Quinn Dunki put it, "a machine tool removes shavings from metal stock with a cutting edge made of a harder metal. It’s just like shaving cheese with a grater, but several times more bad-ass." Ithaca Generator now has a South Bend Lathe and a Mini Mill. Some of the information on this page also applies to use of the drill press and other tools, especially for cutting metals and plastics.
Quinn's series of concise beginner-oriented instructional videos on machining subjects. She also has the great blog linked above.
Cutting Speed and RPM on the Lathe and Mill (For the lathe, use the diameter of the work instead of the tool.)
This Old Tony:
Making A Lathe Chuck Back Plate (Examples of various operations, including boring tapers)