Rebar is used as a reinforcing support for several recipes. It is crafted in the Rolling Machine from a wide variety of metals.
Refined Iron is probably the most efficient way to make rebar, because it only requires iron, while steel can take a long time to produce and bronze requires tin and copper.
The recipes that require Rebar include the Stone Tie, Stone Post, and the Block of Concrete. If the Factory module is not installed, alternate recipes that do not include Rebar will be used for these items.
With 3 Iron Ingots:
With 3 Steel Ingots:
With 3 Bronze Ingots:
With 3 Refined Iron: