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...what's weird to me, in this thread, is that this sort of stress cracking in a bicycle head tube is a relatively common occurrence on steel frames. Frame guys who work on/with steel see it all the time, and the proper repair is invariably to replace the failed head tube. That's the sort of repair you can stand behind with a guarantee. Even in a material as easily welded as steel, I know of nobody who does this professionally who would just run a weld bead on a head tube that has already failed once, and call it good.
I had a very tiny crack in the bottom of the lower head lug on a Raleigh Pro once. It was on a fairly nice early one, that I wanted to repaint, and did not involve the tube, only the lug into which it was inserted. You could barely see it, but it was definitely cracked there. That was repaired with a weld, but not without first cutting a small V, to insure full cleaning and penetration to the bottom of the crack.
Certainly that frame is repairable. As already recommended, either the original company, or another bicycle frame person who regularly works with this metal will replace the failed tube for you. But unlike the best things in life, it's not free.
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