Section
Vintage
Identify what you found. Griswold, Wagner, gate marks, heat rings, and what old iron is worth.
What Is a Heat Ring on Cast Iron? (And Why Collectors Argue About It) A heat ring is the raised ridge circling the underside of old cast iron. What it was for is debated; what it signals about age is useful. Here's how to read one. 
Wagner Ware Cast Iron Identification (Reading a Sidney, Ohio Pan) Wagner marked its iron many ways over the decades — arc logos, the Sidney -O- stamp, bare pattern numbers. How to read each mark and judge the pan under it. 
Griswold Cast Iron Identification: How to Read Every Mark on the Pan Flip the pan and read it: Griswold's cross-in-circle logo eras, ERIE marks, size and pattern numbers, heat rings — and the tells that expose a reproduction. 
What Is a Gate Mark on Cast Iron? (Reading a Pre-1890s Pan) A gate mark is the scar across a pan's bottom where molten iron entered the mold. It signals roughly pre-1890s casting — here's how to read one and cook on it.