Hardening Bucket

The Hardening Bucket is an extension for the Wooden Anvil, not a workbench of its own. Built so that it touches the anvil, it lets the anvil make Bronze Details and the bronze axe, pickaxe, hammer and shovel. Without it those recipes are listed but will not start.

It costs 4 Wooden Planks and 8 Bronze Nails and comes with the second Bronze Works technology (30 red), the one that also unlocks Bronze Details. The technology screen shows both, but nothing on it says the bucket is required.