Lovely! I don't know what it is either.

The carving on the bentwood cover might hold a clue to who made the machine. I remember seeing another cover here on the board that had carving on it a while back. That's all I can remember about the carving, but I think it was also a tree or something like it. Your machine has pretty decals on it. I hope you can find more about it.
Taking another look at your machine, I noticed the decals on the hand crank too. That's neat!!

Your machine is just beautiful.......It must have taken a lot of patience to crank with one hand while feeding fabric with
the other hand, especially if you are left handed. Where their is a will there is a way......must have been a very exciting
item in it's time.

I finally found a machine that was close to mine and it was a National, so I found a National website. The moderator there said I had a National Hand Crank Expert B.T. The one I first saw was a National Hand Crank Duchess Expert B.T, but I don't know if mine is a Duchess or not. Thanks for looking. Kay

Ahh so beautiful. I know you are anxious to get this one cleaned up and shining. Congratulations. I am no help in identifying though.