One of the earliest (I believe the 2nd, after a Billings and Spencer model) butterfly knives made in the US, is the Hemming Woodsman. As best I can tell, the Hemming Brothers Cutlery company operated in New Haven, CT from around 1905 to the mid-1920s. It is a large, robust hunting knife. The handles are solid aluminum and the black paint is still mostly intact. The fit between the blade and handles is fairly tight; it cannot be flipped open or closed one handed, but it is easy to open with two hands. In the open position, the lockup is rock solid. Really, this thing is built like a tank. Maybe I'm just lucky and this example wasn't heavily used, but this is one of the best functioning examples of a century old folding knife I've held. This example is in quite good condition.
- Brass latch is retained by a circular brass spring, still perfectly functional in both open and closed position.
- Sturdy carbon steel blade with a fuller, slight clip point and lots of belly. The edge can impact the inside of the handle, but the blade has wide enough tolerance in the closed position that its not forced to slam the handle every time you close it.
- The only marking, on the flat inside of the handle. I don't know if they ever had their patent granted. Bontgen & Sabin patented a butterfly knife in the US in the 1880s. Maybe the patent just covered the style of latch, which may well have been original.
All the information I can find on these knives seems to be folks posting on forums, repeating the same information from other forum posts. No shame in that, but I'd love to find some primary sources, i.e. period advertisements, catalogues, company literature, patents, corporate registration, etc.
