I had the use of my front wheel drive Snapper push mower for only ten hours. The cut was set too low and I hit a tree root.. A bent crank shaft was the result. I replaced the engine. The pulley for the drive belt had the usual key. The blade adapter was a different story. It is about two inches long of cast iron with a molded key the full length of the adapter. There is no way for this key to snap off - you hit something very hard and it is goodbye engine. Don't try any close cutting with this mower. I learned my lesson the hard way.