This drill has a very aggressive hook and your drill can choke and stall if it doesn't have enough power. If your drill REALLY has enough power, then when the drill jams, the drill can suddenly snap your hands. So use a variable speed drill and start slowly. The instructions state that you need to install the self-feed drill in a specific way. What they don't tell you is that you can set it up with a smaller protrusion for a less aggressive bite. This can be useful depending on the type of wood you are drilling into.