Lets the player craft some items that use iron in vanilla with iron, copper, or any combination of the two. Changes advancements that grant recipes where relevant. Does not make copper useful for beacons, iron golems, flint and steel, or tools/armor, thus does not make iron obtainable from copper. Aims to allow for conservation of iron.
Changes the recipes for:

• Activator Rail
• Anvil
• Blast Furnace
• Bucket
• Cauldron
• Compass
• Crossbow
• Detector Rail
• Heavy Weighted Pressure Plate
• Hopper
• Iron Bars
• Iron Door
• Iron Trapdoor
• Minecart
• Piston
• Rail
• Shears
• Shield
• Smithing Table
• Stonecutter
• Tripwire Hook

This means that some crafting, like making an iron door out of copper, looks kind of silly. If you feel inspired to make a pack that changes this by, for instance, making copper/iron-ambiguous textures or making separate textures for copper shears, feel free to use this pack as a base!