Christopher Polhem Christopher Polhem (1661–1751) was born on the Swedish island of Gotland and was originally named Polhammar. He adopted the name of Polhem when he was knighted in 1716. Polhem died at age 91 in Stockholm. Polhem was a pioneer and a technological genius. The mechanical engineer and inventor also undertook several study trips through northern Europe. His designs and constructions included hoisting equipment for the Falun mine. He started work on the Kattegatt-Vänern canal and was one of the founders of the Royal Swedish Academy of Sciences. Polhem’s many mechanical inventions include padlocks (the Scandinavian or Polhem lock) door locks that were mounted inside doors – a precursor to modern door locks – clocks, shaft couplings (cardan joint or Polhem knot), and textile machinery. To be able to make and profit from his ideas, Polhem and his childhood friend Gabriel Stierncrona (1669–1723) – who was a baron and chancellor of justice – established a manufacturing works and clock factory in Sund in Dalarna province in 1699–1700. The premises were erected on the site of a disused foundry and hammer mill. The place was renamed Stjernsund, after Gabriel Stierncrona and the original place name, Sund. In practice, the works became Polhem’s experimental workshop and did not generate much profit. Abraham Heyke, the works bookkeeper, took over Polhem’s part of the facility on a lease in 1721. The lease was later transferred to his son-in-law Reinhold Galle Rückersköld in 1728. Polhem left his home at Stjernsund when his wife died in the mid-1730s, and he never returned. Swedish ironworks were regularly inspected and a report on their conditions was submitted to the parliament, the Riksdag. In 1753, Samuel Schröderstierna (1720–1779) was appointed director of more exclusive metalworking in Sweden. He also inspected Stjernsund, and after his second visit in 1754, he submitted a report on the works describing impressive facilities. A large smithy, which houses: two hammer mill forges of the German style. A helve hammer. A malleable annealing furnace for sheet iron. A sheet hammer and a plane hammer – both powered by waterwheel – a tail hammer, and a forging hammer. In addition the premises are equipped with plate shears, cutting and stamping units, a tool hearth and a rolling mill, etc. There was also a hardware factory that made pots and pans, shovels, lamps, window fittings, and so forth. In addition there was a lock factory, which comprised five master craftsmen, who each had their own workshop; some worked alone, while others had a worker or young lad who assisted them. They above all made a sort of external lock, known as a disc lock – based on the invention of the late Mr. Polhem, director of the trade board – as well as a further two external locks and ordinary padlocks. In the manufacture thereof they used punches and a variety of other suitable tools to facilitate the work.