They are unlocked at experience level 1.
They are stored in the barn.
A sure way to get a screw is to buy it with 8 dia.
Screws can also sometimes be found in roadside shops for 1 to 270 coin per screw.
Finally, screws can be randomly obtained when players:
- harvest crops
- collect products or animal goods
- cut down trees and bushes
- feed pets
- open mystery boxes and mystery packages
- spin the Wheel of Fortune
- participate in global events
- fully satisfy a town visitor
- win prizes in derbies
- use mystery nets in the fishing lake
- watch a Night at the Movies trailer