I’ve been wondering what kinds of oils were used for oilstones prior to petroleum distillates. It seems like most light oils are also drying types, which would be a problem.
Waterstones are nice, but can’t be allowed to freeze. And diamond stones aren’t reproducible in a non-industrial situation.
Good question. I bet Japanese woodworkers would know.
Not claiming to know, but I’ve sharpened a knife or a tool on a smooth stone with just water. There’s also body oil, not usually enough of it.