I think I would turn the largest slip fit solid bronze (SAE 660) pin I could, ignoring the egg, then fill it with the low temp silver solder that pd mentioned. Then properly locate the hole and drill/ream to fit. That way you wouldn't be removing any original material, weakening it, then the silver solder would strengthen it by bonding to the solid pin. Pretty much a new blank at that point, then put the right hole in it.