I have a 1" threaded fork for a steel DeBernardi frame I'm contemplating rehabbing and putting back on the road. The topmost ~1/4" of steerer thread is semi-flattened, to the point that the headset lockring doesn't bite anymore, so the headset won't stay tight. I'm not wild about threaded in any case - I much prefer threadless for its simplicity and ease of setup.
The question: is it possible, or even advisable, to either replace the threaded steerer with a threadless one - either in its entirety by installing a new steerer tube into the crown, or by cutting down the threaded steered and "grafting on" a section of 1" threadless steerer tube? Is it possible to melt the brazing holding the steerer into the crown without compromising the fork leg/crown joints? Or should I bite the bullet and simply buy a new fork? Thoughts?