I don't have any specific recommendations but I will note that in some Eskimo tribes, children are trusted with razor sharp blades from pretty much the day they learn how to walk. When it comes time to cut up the whale, every hand and every blade that can be thrown at the task makes it easier.
You don't hear of those kids cutting their own hands off very often. Early exposure means early learning means early competence means early safety.
Nobody ever cuts himself with a razor blade more than a couple of times. Each time it reinforces the "I'd better not do that again!" lesson. After only a couple of minor incidents you're now going to be safe with a sharp object, probably for life.
So, yes, I believe that it's OK to give an intelligent and reasonable child a sharp object. He'll figure it out.