Jack Romans asked about the possiblity of repairing his cracked frame. I'd be curious to know how the damage occured in the first place. If it was "just riding around" (JRA), I'd be surprised. If it had seen some severe trauma (crash etc) seems more likely.
Note: My opinion is not that of a professional framebuilder. If the crack is in the lug, I would braze or silver solder the crack rather than fillet the whole thing. Even if the crack extends into the tube, the repair is still possible. It seems a shame to slather on a bunch of brass to a lugged frame.
Relacement of the head tube and downtube seems like more work than it's worth for a basic frame. If it was a collectable, personally cherished item, then perhaps. I'm sure others will have opinions.