But one day he heard a strange noise at his feet, and when he looked down to see what it could be, he saw a stone-cutter driving tools into his surface.

It happened that a stone-cutter came that way for a stone, and when he saw the one that had been the blacksmith, he knew that it was what he sought, and he began to cut it.

The work principle of underwater cutter of plastic drainage plate, selection of electrical machinery and saw blade, as well as the spacing device of drainage plate, etc. are introduced.