On the Campy 1032 FD, the cable fixing bolt is threaded into aluminum, so after 40 years or so, the threads do strip out, whether from wear or over tightening.
this mod results in a very solid thread for the bolt. It will last another 50 years. Great component.
Modern Campy FDs are in fact helicoiled from the factory in this location.
A nut is (generally) steel so the threads are much more solid
/markp