Photo Via https://pixabay.com/en/magnet-horseshoe-nails-magnetic-29094/ under the Creative Commons License.
The screws were lodestone to the magnet as it got closer.
Something that attracts strongly.
The Declaration • October 26, 2016 • https://thedeclarationatcoloniahigh.com/18881/wordoftheday/lodestone/
Lodestone