Tool & Die Set

The  is one of the three Forge Tools, along with the Anvil and Crucible. It unlocks the Forge's full potential, because it is needed to be able to craft certain items in the forge. It can sometimes be found as rare loot inside Working Stiffs Crates, occasionally purchased from Traders, but cannot be crafted.

Tutorial
The video below demonstrates where to find the Tool & Die Set, which wasn't found this time.

Werkzeugset