Finger claws and bowl lips can be used for it. It runs very fast, but it is strong, slippery and easy to drop. It is best not to hang up.
Bowl lip rotation and nail rotation are both acceptable. The rotation is flexible (due to low friction), but it is easy to fall off. It is best to use the hanging method.
Regarding the installation method of the magnetic needle, Shen Kuo introduced four methods:
1 Shui Piao-Just put a few wicks on the magnetic needle to float on the water, which can indicate the direction.
2 bowl lip rotation method-put the magnetic needle on the edge of the bowl mouth, and the magnetic needle can rotate to indicate the direction.
3 nail rotation method-put the magnetic needle on the nail. Because the nail surface is smooth, the magnetic needle can rotate freely to indicate the direction.
Four-strand suspension method-coat some wax in the middle of the magnetic needle, stick a silk on it, and hang it in a windless place to indicate the direction.