Hi,
I have a Schwinn Voyageur SP - Columbus steel frame (circa 1985)
the previous owner changed the fork from the original Columbus Steel to another one which is missing the Braze Ons for the front rack (mid fork) and the 2 eyelets at the end of fork for the fenders and rack.

Question: Does anyone know where I can find this original fork?
(other then craigs list or ebay, I have already looked there).
thank you.

I doubt you'll find the original fork, however there is this:
https://www.universalcycles.com/shopp...&category=1640

I have this same fork (bought for another project), as well as an '85 Voyageur S/P (ugly blue). I just checked and it's pretty close in measurement to the stock fork on my S/P. It only has single eyelets below the fork, but IME most lowrider racks work best mounted on the lower eyelets anyways.

thanks, that is helpful. I was told that most likely this frame requires a threaded fork.

The frame came with a threaded fork, and you probably have a threaded headset on it now (depending on what the previous owner changed), but it really on requires a 1" fork. You could get a 1" threadless headset and a 1" threadless fork and it would work just as well as a 1" threaded headset and 1" threaded fork.