Tin Gears are materials used in Electrical Engines.
This article contains material that is not in the current version of Tekkit.
The content you see here is not available if you are using the current version.
If BuildCraft is not present, the Tin Gear recipe is as follows:
If BuildCraft is present, the recipe stays basically the same, however a Stone Gear in the center is required.
Other Gears are available from BuildCraft.
Tin gears have been removed as they are part of the Forestry mod, which was removed some time ago.