Medieval engravers were guild members who created coins in mints. The vast majority of medieval coins were cold struck; the planchets were not heated. Medieval coin dies were largely made of iron. Early medieval coinage was dominated by dies created mostly from punches, which displace the metal of the die instead of removing it. In the late Middle Ages, the dies used to create tornesellos lasted as follows: "hammer" die, 17,000 strikes; "anvil" die, 36,000 strikes. The mint made an average of 20,000 coins per day, so they were making one hammer die a day and one anvil die every other day. The "hammer" dies wore out quicker because they tended to be smaller and were hit directly with a hammer, leading to severe mushrooming on the tops. I