- "A screw used in ancient machinery. It's made of an unknown material and no mattter how many times it's turned, its threads never seem to show sign of wear."
- — In-game description
Ancient Screws are materials in The Legend of Zelda: Breath of the Wild. It is a Guardian Part obtained by defeating certain types of Guardians, by searching broken Guardians, or lifting legless Guardians near sources of water using the Cryonis Rune. Link can also purchase them from the traveling merchant Teli who travels around the Necluda province. Like all Guardian Parts, it is a piece of ancient machinery created by the ancient Sheikah.
Ancient Screws can be used by Great Fairies to upgrade certain armor. At the Akkala Ancient Tech Lab the Ancient Oven Cherry can use them to forge certain types of Ancient Soldier Gear after Link relights its Furnace during "Robbie's Research". Additionally like Monster Parts, Link can use them to create Elixirs by cooking them with Frogs, Lizards, or Bugs.
Related Side Quest
In the Side Quest "Slated for Upgrades", Purah offers to upgrade his Sheikah Sensor if he brings her three Ancient Screws. After bring her the necessary materials, she will allow him to use her Guidance Stone to upgrade the Sheikah Sensor to Sheikah Sensor+ which links it to the Hyrule Compendium allowing Link to search for objects recorded in the compendium. Additionally Symin will ask to see the new upgrade which leads to "Sunshroom Sensing" side quest which acts as a Sheikah Sensor+ tutorial.