Off-hand, I'm not sure engraving is really necessary. In aerospace, where there is a possibility of ingestion or being lost in a critical area where catastrophic failure would require tool identification, engraving makes sense as it can't easily be removed (as we did in the AF, etc.), fall off, burn off, etc.
But on an assembly line? They make paint sticks, even acid etching would work if you're worried that the vibration from the engraver would affect the tool.
Now, how about laser engraving? Works great if you have one, and no impact to the tool. The ID alpha-numeric can be made quite small in out-of-the-way locations and be perfectly legible.