Why Medieval Nails Held for 800 Years While Modern Fasteners Rust in Decades

From Medieval Way

Medieval Way explores the historical craftsmanship behind incredibly durable ancient iron, contrasting it with modern industrial manufacturing. By analyzing archeological findings and the science of corrosion, this investigation reveals why traditional forging techniques achieved longevity that contemporary steel fasteners fail to replicate.

Somewhere on your property, a piece of metal is quietly failing. The screws in your deck, the nails in your fence, the hangers under your porch. Manufacturers rate them for twenty or thirty years, and in the wrong wood they can be gone in five. Yet in Westminster Abbey hangs a door dated by its tree rings to the 1050s, still swinging where medieval hands left it. That iron was forged by men who could not read, in furnaces that never got hot enough to melt it. Why does their metal outlast ours by centuries? The answer spent nearly two thousand years buried in a Scottish field. And when it finally came out of the ground, the people who lined up to study it were engineers designing containers for nuclear waste. Perthshire, Scotland, 1960. Archaeologists led by Sir Ian Richmond were closing out years of excavation at Inchtuthil, a Roman legionary fortress on the River Tay, when they cut into the floor of the fortress workshop and hit a pit twelve feet deep. Inside lay more than 875,000 iron nails. Around ten tons of metal, everything from two-and-a-half-inch tacks to fifteen-inch spikes, the largest single hoard of Roman ironwork ever found, before or since.