fork fabrication
it would seem to me that the 1906-1940 Sager springer fork would be a natural to fabricate, as these were mass-produced with rather primitive tooling. If you have a lathe, hacksaw, welding apperatus and access to aircraft steel tubung and springs of the right diameters as well as some mechanical apptitude, it should be fairly simple. What is a Sager? Check out the 1907-1919 Harley Davidsons and that's what you see.
the Old Sgt.