How to make a compass (compass needle) in the Song Dynasty by hand?

Compass preferably with copper, engraved on the front to be engraved in the middle of the grinding out a small concave, the magnetic spoon is not very good to do the magnet chiseled into the grinding, the more crushed the better, in the use of the brother and sister of the good glue mixed together with the living well with a spoon to do the mold after drying sandpaper polished smooth, & lt; magnetic powder and glue with the right amount of & gt;