Chainsaw oil, or bar and chain oil, lubricates the guide bar, chain and drive sprocket on chainsaws and forestry cutting equipment.

The chain runs at high speed around a tight radius, which throws lubricant off aggressively, so tackiness is the defining property. Tackifier additives make the oil stringy so it clings to the bar rail and chain links long enough to reach the cutting zone rather than flying off at the nose. Good bar oil also cools the chain, flushes sawdust out of the bar groove and protects against rust on equipment that stands between jobs.

Using old engine oil instead is a false economy. It has no tackifier, is thrown straight off, and leads to rapid bar and chain wear that costs far more than the oil saved. Check the oiler is feeding before each session.