I have an idea for you. Its not the best drawing ever, but i think you can tell whats going on. If you can't well you get a lathe and turn off a peice of metal the same size as your steerer. Then bit down the post you cut a little bit extra off. 2 mm bigger than the center of your steerer. Then you make a thread on the inside of your steerer and on the outside of your new peice of turned off metal. Then drill a hole in your peice of metal the same size as the hole was on the inside of your steerer so that your starnut will go in.(Don't go all the way through your peice of metal of you will spoil your thread) Then you cover both threads in loctite and screw togather as tight as possible. Wait for the loctite to set in. Then ride. Not sure if it will work but worth a try I'd say would say it will be stronger then welding it. Matt Rushton