Its a girder fork, not sure what it is from. Kind of looks like the fork from an old jawa motorcyle/moped that my brother had.
Looks like a ratrod fork to me :mrgreen:
Those are some fine forks. They might be worth posting on a vintage moped/motorbike site, I bet someone could ID them pretty fast. As far as I know, they never came on bicycles, originally but they sure do look great on them now :mrgreen: