We have probably about beat this to death, and people's existing opinions will mostly remain intact. For my mill and lathe, I use the oils specified in the manual. Not necessarily the brand specified, but the same spec oil. For my car, I use the grade and viscosity of oil and other lubricants specified in the manual. For protecting parts and tools from rust I use ATF, the cheaper the better. I try to consciously ignore all advertising, hype, and internet opinions and simply buy the specified lubricants at the best possible pricing. Works for me so far...