When biodiesel is made glycerin is a byproduct. In our case when making lubricant we are adding glycerin.

http://en.wikipedia.org/wiki/Biodiesel
http://en.wikipedia.org/wiki/Synthetic_oil

Biodiesel does improve the lubricity of blended fuels. It's more viscous compared to petrodiesel. If viscosity of the blend increases from 2cSt to 3cSt this is a big change. That is great news for a diesel pump which only needs 1.8cSt viscosity fuel to survive. That doesn't make it a good lubricant for friction bearings. Most B100 solidifies above 0C. Soy Gold says their fuel has a viscosity of a bit over 4cSt.

You have to careful reading crap on the internet. Everyone has an agenda. I do not believe anything until I've seen the same information in a university study or several different sources. Higher viscosity is great fromt he standpoint of lubrication. Injection varies with viscosity so it might not be good as spray patterns deteriorate with increased viscosity. But biodiesel is required to be within the specified range for diesel fuels. Straight vegetable oils are not.

Is mineral spirits cheap? The hardware store cost is ~10USD per gallon. Hardware store Kerosene is ~8.50, and Pump Kerosene is under 3USD around here. Kerosene has a significantly lower auto ignition temp so I'm not sure why we want to stray from kerosene. Properties of mineral spirits seem to be similar to No.2 Diesel.

Auto ignition temperature of napthas in lighter fluids seems high at 300+C. Flash and poiling points are low.

Naptha by the way is a very general term. Gasoline and kerosene are considered napthas.