I bought this to cut holes in sheet steel for car dashboards. As it was being removed from the protective plastic box, it hit the drill, hitting my arm and ripping off a small piece of skin. The thing is super sharp. Handle it with care. Also wear hearing protection. He cut a very smooth hole that subsequently required minimal hand tools. I didn't have to cut many holes so I don't know how long it will stay sharp but the last hole will be cut the same as the first. You also need cutting oil.