From Junk Jack Wiki
 Crafting Furniture
Crafting furniture are required to craft some O-Items. To use them, Jack needs to be within one square from them. Then they are used automatically when crafting. In 1.1, the crafting background will differ depending on the addon used.
- O-Workbench is the most basic crafting furniture and it is required to build all furniture elements (doors, windows, etc)
- O-Forge is used to smelt ore into O-Ingots and cook meat to heal you faster.
- O-Anvil is used to craft O-Ingots into Metal Tools