Short answer
The Smithy is a Factory workstation: zombies work its recipes on the conveyor line. Smithy I (75 red, 20 blue, after Iron Smithing) builds for 6 Reinforced Plank, 4 Bronze Detail and 4 Bronze Gear and makes Brick and Glass. Iron Ingots and Iron Kits need the Smithy: Hammer extension built next to it. Smithy II (160 red, 20 blue) adds Clay Molds, Iron Kit II, Engineering Kit, Steel Tools and Lens.

The Town workshop
View full-size image ↗Official promotional screenshot · © Lazy Bear Games / tinyBuild · Official media kit · Material credits
Smithy I
Technology: Smithy I, Metallurgy column 8 — 75 red, 20 blue. Needs Iron Smithing (50 red).
Build in the Factory: 6 Reinforced Plank, 4 Bronze Detail, 4 Bronze Gear.
Brick — 2 Clay + Coal → 2 Brick. Glass — 3 Sand + Coal → 1 Glass. Both 8 ticks, Smithing mastery 2.
It takes no fuel; every recipe uses Coal as an ingredient instead.
The four extensions
Smithy: Hammer (80 red, 30 blue) — 2 Wooden beam, 2 Iron Detail, 1 Iron Ingot. Unlocks Iron Ingot (Iron Ore + Coal) and Iron Kit I (1 Iron Ingot → 4 kits, mastery 3).
Smithy: Bellows (90 red, 20 blue) — 4 Leather Scroll, 2 Iron Detail, 4 Wooden Plank. Unlocks Glass Containers and Tableware (mastery 4) and is required by Iron Kit II, Engineering Kit and Steel Tools.
Smithy: Press (from Lenses) — 2 Engineering Details, 4 Steel Detail, 2 Wooden beam. Needed for Lens.
Smithy: Grindstone (from Steel Works) — 2 Engineering Details, 4 Steel Detail, 1 Piece of stone.
A recipe that needs an extension will not run until that extension stands next to the Smithy.
Smithy II
Technology: Smithy II, Metallurgy column 14 — 160 red, 20 blue. Needs Steel Casting (150 red, 20 blue).
Built separately for 6 Reinforced Beam, 12 Steel Screws and 4 Engineering Details. It keeps all six Smithy I recipes.
Clay Molds — 2 Clay + Coal, mastery 5. Iron Kit II — 1 Iron Ingot + 2 Clay Molds → 4, 12 ticks, mastery 5, needs Bellows.
Steel Works (175 red, 20 blue) adds Engineering Kit (Steel Ingot + 2 Clay Molds, mastery 6) and Supply: Steel Tools (4 Steel Ingot + Crate, 12 ticks).
Lenses (175 red, 20 blue) adds Lens — 3 Sand + 2 Coal, mastery 7, needs the Press.
Original diagram of a starter Factory line. The Smithy is a Factory workstation fed the same way.
View full-size image ↗Original diagram · Graveyard Keeper 2 Wiki · editorial illustration · Original wiki diagram
Staffing it
Every recipe costs 2 energy per tick for the zombie and pays it red tech points (1 to 4).
The zombie's Smithing mastery must reach the recipe's level — tools like a hammer add to it, and the Novice, Advanced and Master Blacksmith zombie perks help too.
Coal comes from a Zombie Miner in the Old Mine, so a steady Smithy needs that line running.
Sources
- communitywikily.gg — Smithy I
- communitywikily.gg — Smithy II
- communitywikily.gg — Smithy I (technology)
- communitywikily.gg — Smithy: Hammer
- communitywikily.gg — Smithy: Bellows
- communitywikily.gg — Smithy II (technology)
- communitywikily.gg — Steel Works
Related pages
Official screenshot · © Lazy Bear Games / tinyBuildCraftingGraveyard Keeper 2 Iron: Ore, Ingots and the Smithy
Official screenshot · © Lazy Bear Games / tinyBuildCraftingGraveyard Keeper 2 Iron Kit I & II
Official screenshot · © Lazy Bear Games / tinyBuildCraftingGraveyard Keeper 2 Coal
Official screenshot · © Lazy Bear Games / tinyBuildAutomationGraveyard Keeper 2 Factory Layout & Setup
Official screenshot · © Lazy Bear Games / tinyBuildEconomyGraveyard Keeper 2 Steel Ingots and the Steel Anvil