How Mints Actually Strike a Coin: From Blank to Finished Piece

A finished coin looks like a single, simple object, but it’s the end of a fairly involved manufacturing process. Understanding the steps — and how radically they’ve changed over the centuries — makes it much easier to appreciate why coins from different eras look and feel so different in hand.

From metal to strip

Modern minting starts with metal already alloyed to the correct specification, delivered to the mint as coils of strip metal of the right thickness. The strip is fed through a blanking press, which punches out flat, round discs called planchets — essentially large sheets of metal turned into a field of coin-sized holes, with the leftover webbing recycled back into the melt.

Those raw planchets then go through an annealing furnace, which heats and slowly cools the metal to soften it, since work-hardened metal straight from the rolling mill would be too brittle to strike cleanly. After annealing and a wash to clean the surface, the planchets pass through an upsetting mill, a machine that squeezes the outer edge of each planchet to raise a small rim. That raised rim does two jobs: it protects the coin’s highest design points from wear in circulation, and it helps the metal flow correctly into the design during striking.

The strike itself

The finished planchet is fed between two engraved dies — one for the obverse (“heads”) and one for the reverse (“tails”) — held inside a coining press. A metal collar surrounds the planchet during the strike, both to keep it centered and, on many coins, to press the reeded or lettered pattern into the edge at the same moment. The press then brings the dies together with enormous force, and in a fraction of a second, the design transfers from both dies into the metal simultaneously.

Modern coining presses can strike hundreds of coins per minute, and business-strike coins for circulation are typically struck only once. Proof coins, made for collectors rather than circulation, are usually struck twice or more using specially polished dies, which is part of why they show a sharper, more mirror-like finish.

From the hammer to the screw press

This mechanized process is a relatively recent development in the multi-thousand-year story of coinage. The earliest coins, starting in ancient Lydia around the 7th century BC, and the vast majority of coins struck across the ancient and medieval worlds, were hammered: a planchet was placed between two dies, one often set into an anvil and the other held by hand, and a mint worker struck the top die with a hammer to transfer the design. Hammered coins are recognizable by their irregular, often slightly off-round shape and inconsistent centering, since every strike depended on a human hand aligning the dies by eye.

The screw press, adapted for coining in Renaissance Europe and adopted more widely through the 16th and 17th centuries, replaced the hammer with a heavy weighted screw mechanism, giving a more consistent, centered strike and allowing round, uniform planchets for the first time. It was a major step toward the mechanized “milled coinage” that eventually replaced hammered coins entirely across most of the world.

The steam-powered leap

The next major leap came at the end of the 18th century, when Matthew Boulton’s Soho Mint in Birmingham, England, applied steam power to coining presses. Boulton’s steam-driven machinery could strike coins faster, more uniformly, and with a raised rim and edge lettering that was far harder to counterfeit than anything hammered coinage could produce. Mints around the world gradually adopted steam and then electric power over the 19th century, and by the 20th century, hand-operated coining had essentially disappeared from official mints.

What this history tells you

Knowing this process helps explain a lot of what you see when you examine a coin. A slightly off-center, irregularly shaped hammered coin isn’t damaged or a mistake — it’s simply a product of hand striking. A crisp, perfectly round, evenly struck modern coin reflects a century and a half of mechanical refinement. And features like reeded edges, raised rims, and sharp, consistent detail all trace back to specific technological steps in minting history, not just aesthetic choices.