That flare will not hold. Cut it again and rim (deburr) using rimmer. Be careful not to get copper pieces in there... not sure how I would go about on already brazed line pointing up like that... What you are thinking about probably is double flare... Flare should look perfectly cylindrical with smooth surface, etc. Even nut might not be able to hold one you made there... Also, it looks like you flared too far out which might work against thread. Moderation moderation