I've seen various "natural" cutting and tapping fluids such as
"tapmatic natural" which claim to be esters of some sort of vegetable
oil. They also have a "citrus spice" scent which leads me to believe
they are either an ester of orange oil or a mix of orange oil and
biodiesel. My bedroom is right next door to my lathe so I don't relish
the thought of regularly using sulfurized cutting oil or kerosene.

With biodiesel so cheap (free for me) and less toxic than water
according to the MSDS, I was thinking of using it as a flood
coolant/lubricant. Does anyone know of any major disadvantages of using
biodiesel in this way?

-ben lipkowitz