Originally Posted by
JohnDThompson
Without intact threads, there's nothing to hold the cup in a stable position. If you adjust it so the bearings rotate smoothly, the cup will wobble on the steer tube (try it if you don't believe me -- it may work for a short while in the work stand, but not on the road in the long term). If you adjust it so the cup doesn't wobble, the the bearing will not turn smoothly.
You really do need to either fix the threads or replace the fork.
+1 agree with this.
I think that the op is thinking is to press the race cap with spacers and similar to a threadless headset. This will not work well because of the existing damage to the threaded portion of the steerer. there are no longer the close tolerances neccessary to prevent the race cap from wobbling and will eventually cause more damage to the steerer and the races and bearings. This is something that should be fixed the correct way.