Nice find. All you need is a boys DX frame and you can build yourself a nice bike. That birdwing chainguard is nice and straight. I'm guessing that bike is a '40 or '41 by the guard and "upside-down" Wald neck. The lock in the fork makes it a half inch longer than normal. If you cut new threads and shorten it for use on a prewar boys frame you can use post war truss rods and they fit fine. I've got one set up like that. Gary