Unlike any rotary blade tool I've owned, this one comes with no locking mechanism. Using this tool is dangerous, especially at high speeds. When the drill stops, the 6-inch blade keeps spinning and flies off the shaft at almost the same speed it was spinning at. I definitely wouldn't order this tool if I knew it didn't have a lock nut or mechanism to lock the blade to the shank. I know from experience that trying to catch that blade while it's spinning to keep it from hitting the clean floor will cut you. This product should not be sold as is. This blade should have at least one danger warning.