Rather than buy a real Nardi horn button and mess it up trying to do this, I bought a Chinese copy for $20 on Ebay. Nardi does not make a Sunbeam one anyway.
So I took it apart and and cut the top off of the center button. Then I bought a new grille center emblem from Sunbeam Specialties and turned it down on a lathe to the same diameter. I super glued them together, then JB Welded them for good measure after fitting the pieces. Then I beveled/rounded the edges, sanded and polished the center emblem. There was a little more massaging of pieces as I changed how far the emblem sticks out of the wheel, so I had to modify the spring and cup inside for less depth.
Overall, I think it's a winner.
So I took it apart and and cut the top off of the center button. Then I bought a new grille center emblem from Sunbeam Specialties and turned it down on a lathe to the same diameter. I super glued them together, then JB Welded them for good measure after fitting the pieces. Then I beveled/rounded the edges, sanded and polished the center emblem. There was a little more massaging of pieces as I changed how far the emblem sticks out of the wheel, so I had to modify the spring and cup inside for less depth.
Overall, I think it's a winner.