42 1 1/2 Ton Truck Steering wheels .

[BouncinBetty]

Horn button retaing guts on my truck missing , i bought a 1940 wheel and thought i would remove the centre button mounting and fit to my wheel as it looked in better condition , managed to get the metal cup out off wheel but it will not fit my wheel ,it seems my wheel contains more material with a step so the cup can not sit down , i could fit the locking ring on top of this material but i would have to split it from the Cup and then glue it in place somehow .Did they do away with the cup sometime to save material but not being as secure is why my horn button is lost ? Both wheels are 4 spoke truck type , any ideas .