Juergen Hannappel wrote:

"dean" writes:

Because every professional user I have ever seen is using 10W30 engine
oil. Now I'm not about to put that into my Stihls but I was just
wondering if I am wasting money on expensive bar oil?

The oil on the chain will be distributed in you environment it's
totally unacceptable to use a non-biodegradable oil for lubricating
the saw. The pro's you have seen obviously don't care a dam about the
rest of the world and should be [insert punishment of choice]...

Well, they are cutting trees, aren't they, the scum...

I really doubt the base of bar oil is any different than that for engine
oil...just viscosity and (perhaps) some specific additives, but I'd not
expect much there as the lubrication requirements are not onerous in
terms of temperature, pressure, tolerances, etc.