I believe but cannot prove, nor does it matter, that Voigtlander USA produced these beautiful lenses for the Thornward name to be sold by Monkey Wards. The machine work is interchangeable with my other 1890's era Voigtlander lenses, especially the USA ones. I've used it. Spectacular to hold and use. Wish I had the flange but no such luck on this one. If you have an early 36cm Heliar this might just spin right in the flange for that. When I used it last summer I borrowed the flange from my 15" Serie II Voigtlaender Euryscop. It's a gorgeous piece. The matching waterhouse stops are numbered for the old US system. Thread width at the flange is exactly 4" / 101mm.
Once in a life time piece. When it's gone I don't expect to see another. $950 + shipping