Iron Stairs are building blocks cut into an L-shape looking like made of very rusty iron.
Usually placed as stairs they will smooth the player-character's movement up and down gradients so no jumping is necessary. They can be placed as projections of walls or for other purposes too when being rotated by pressing and holding R (as the default key) while moving the mouse.
Iron Stairs can be crafted in your Crafting Menu (default key "q"), but only after the according crafting recipe has been unlocked by
- smelting Iron Bars by putting Iron Ore into a Forge together with some Fuel. Iron Ore can be extracted from Iron Nodes found on the Stalactite layer underground or can be found in Iron Treasure Chests or Diamond Treasure Chests
- crafting or taking Iron Walls
- crafting or taking Obsidian Stairs (unlocked after crafting/taking Stone Stairs)
Crafting or taking Iron Stairs is one of the unlocking requirements of the crafting recipe for Diamond Stairs.
To craft 4 (blocks of) Iron Stairs, you'll need
- 2 Globs of Goo made from Mold in a Processor or looted/harvested from creatures
- 2 Iron Slabs made of Iron bars in a Processor
- 1 Obsidian Rod made of Obsidian bars in a Processor