Steve,
It is interesting to try a little test. Take a drop or two of boiled oil, same of the artist's oil and smear some on a piece of clean steel or glass, and see how long it takes to dry. Try the same with a little cobalt drier or Japan drier, about 50;50 see how it dries. In my limited experience, raw oil with out any drier takes very long to dry, maybe never. But it does a great job of bringing out the wood color and grain.

Dennis Potter