I have a Never Been Built '84 Schwinn super sport frame. It did not come with a fork. I need to source a 1" threaded fork. I do not have an existing fork to measure. I also have none of the associated hardware that goes with the headset, (ball bearings, adjusting and locking nuts). The headset is a Tange falcon.

The distance between the centerlines of the upper and lower bearing races, (As close as I can guess as to the center of the ball bearings) is 212 mm.

What would the appropriate steering tube length be?

Thanks for your help!

Gary