That's why I wrote the post on defining milling. In my mind, there is a difference between screwing (using a screw press) and milling (producing in a mill). That difference is the source of energy. The Dutch mints used human energy until steam presses became available. I am not even sure they started using non-human energy in the 1790s, but it is a logical date and the coins of the 1790s do look better and are much more often found in higher grade than earlier coins (disregarding off-metal strikes and quarter guilders here, as they were not struck for circulation). The designs were not too different, but the coins are more often perfectly round, well centred and deep struck.
Indeed, the 16th century milled coins (Mestrell in England) are mostly failed experiments. The second wave of milled coins, in the 17th century, using horse power (Briot in England) stayed on. I would argue that Segovia was the turning point. It did not close its milling production line, but for a long time, it remained the only Spanish mint producing milled coins. During that time, milling went from luxury and artsy to the mainstream coin production method.
Usually, the minters and their guilds are blamed for the early failures, but French and English mint masters are on record opposing milling also. I think it is far more likely that the early machines had much downtime, making them uneconomical. Later machines were more precise and therefore cheaper to operate and producing faster.
I have been looking for data and evidence of Russian use of water power for coinage. So far, all I have is a vague memory of reading they did. There may yet be a surprise coming from Russian history.
Peter
