If used in a Thermionic Fabricator it can make Gears depending what you put in the melting slot. You put the cast in the upper right corner
If you put in Iron, Copper, Tin or bronze you will need to put a Stone Gear in the middle
If you put in Gold you will need to have a Iron Gear in the middle.
If you put in Diamond you will need to have a gold Gear in the middle.