Part of a competition piece I did a few years ago was on Viking Knit (Trichinopoly) where I learned a lot more about draw plates, and specifically 11th century draw plates. These are (in short) used to make wire a smaller diameter – as well as taking down the diameter of completed Viking Knit.
One of the items in the Royal Alberta Museum (RAM) exhibits was about draw plates, along with other metal working / jewelry making tools.