The story of the second grade Lu Ban and the plane What is the plane and what is its composition?

The story of luban and the plane in the second grade. This plane consists of an axe and iron pieces. In the story, Lu Ban grinds a small axe and covers it with a piece of iron, leaving only a narrow blade. This time, Luban won't cut it. He pushed the wood with this narrow blade. Push, the wood pushed down a thin layer of sawdust. After a dozen pushes, the surface of the wood is flat and smooth, which is much better than that cut with an axe in the past. But when this thing is pushed in your hand, it is both stuck and invalid. Lu Ban made another wooden pedestal and put it in. So the plane was born.